JP4682719B2 - Wireless communication system and method for adjusting communication frequency of wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system that performs communication using radio signals and a method for adjusting a communication frequency of the radio communication system.

  In recent years, communication devices using wireless communication, such as cordless telephones and wireless door phones, have been widely used in general households.

  These wireless communication systems are composed of a wireless communication system that operates as one control station and one or more dependent stations. For example, a cordless telephone for home use is composed of a cordless telephone master connected to a public network that operates as a control station and a cordless telephone slave that operates as a subordinate station. A telephone call is made to the public network via the machine, and an extension call is made between the parent machine and the child machine using wireless communication. In addition, the wireless door phone is composed of a door phone master unit that operates as a control station connected to the entrance slave unit and a door phone slave unit that operates as a subordinate station. The door phone slave unit is connected to the entrance phone via the door phone master unit by wireless communication. It communicates with the machine, responds to the visitor who has called by the front-end child machine, makes a call with the visitor, and makes an extension call between the parent and child machines or between the child machines using wireless communication.

  As described above, wireless communication systems such as cordless telephones and wireless doorphones are widely used in the home, but the parent device (control station) of each wireless communication system corresponds to the application and wireless communication method of the parent device. It can only communicate with slave units (subordinate stations). Therefore, for example, when both a cordless telephone and a wireless door phone are installed in a home, a dedicated handset, that is, a cordless telephone handset and a doorphone handset, is necessary, which increases the equipment cost and is convenient. It was damaging.

  Therefore, one solution to this problem is to provide a slave unit that shares hardware and software for dependent station wireless communication by using the same wireless communication method in wireless communication systems that provide different services. It is. For example, a wireless communication system that operates as a dual-purpose subordinate station that can be wirelessly connected to a cordless telephone base unit that operates as a control station and a doorphone base unit by performing communication in the wireless section of the cordless telephone and the wireless door phone using a common protocol By implementing an application that operates as a cordless telephone slave unit and an application that operates as a door phone slave unit, it is possible to provide a dual-purpose slave unit that can be connected to both the cordless telephone master unit and the wireless doorphone master unit. Become.

In a wireless communication system including a control station and a dependent station, the dependent station needs to receive a control signal from the control station and wait for a call from the control station. In the above-mentioned dual-purpose handset, it is necessary to receive control signals of both the cordless telephone base unit and the wireless doorphone base unit. A technique in which one dependent station receives control signals from two control stations has already been put into practical use, for example, in a personal handyphone system (hereinafter referred to as PHS). PHS has been standardized for the purpose of use in public networks and private networks, and PHS terminals can communicate wirelessly with PHS public network base stations as public terminals, and as private terminals for home use. Wireless communication with other digital cordless telephone masters. Then, the PHS terminal matches each control station (public base station or digital cordless telephone) with a control signal transmitted by the base station of the PHS public network and the home-use digital cordless telephone master unit in accordance with the transmission timing of each transmitting side. By setting the reception frequency to the transmission frequency of the control signal of the master unit and receiving the control signal transmitted from each control station, both the base station of the PHS public network and the digital cordless telephone master unit for home use It is possible to wait at the same time (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-87556

  When implementing a slave station (shared slave unit) that can be connected to multiple control stations (for example, cordless telephone master unit, wireless doorphone master unit, etc.) during wireless communication between each control station and dependent station (slave slave unit) It is necessary to realize the same wireless performance as the wireless performance in the case where communication is performed between the control station and each dedicated subordinate station.

  One of the causes of radio performance degradation is degradation of reception quality due to a shift in radio communication frequency between a control station and a subordinate station. In a radio communication system, in order to suppress this degradation of reception quality, the transmission side and the reception side The frequency shift of the high frequency signal generated by the high frequency generation circuit for wireless communication must be reduced. Wireless communication between the control station and the subordinate station is performed at a predetermined frequency, and the control station and the subordinate station include a high frequency generation circuit for generating a high frequency signal having a predetermined communication frequency. In a wireless communication system that performs communication by selecting one of a plurality of frequencies, such as a cordless telephone or a wireless door phone, a high frequency generation circuit capable of generating a plurality of frequencies is required. A generation circuit is provided. The basic phase-locked loop for high-frequency signal generation is a voltage-controlled oscillator that generates a high-frequency signal having a frequency corresponding to the input DC voltage, and a frequency-controlled oscillator that generates a high-frequency signal output from the voltage-controlled oscillator. A frequency divider that divides by value, a reference signal generator that generates a clock serving as a reference signal, a frequency divider that divides a clock output from the reference signal generator by a predetermined value, and each frequency divider A phase comparator that outputs a signal according to the phase difference of the output, a filter that smoothes the output of the phase comparator and outputs the control voltage of the voltage controlled oscillator, and is an integer of the output frequency of the divided reference signal generator It operates so that a double high frequency signal is generated from the voltage controlled oscillator. Therefore, in order to reduce the frequency deviation of the high frequency signal generated by the radio communication high frequency generation circuit on the transmission side and the reception side, the difference (deviation) in the output frequency of the reference signal generator must be reduced. .

  When a dependent station (slave unit) performs wireless communication with only one control station (cordless phone base unit) as in a conventional cordless phone, both reference signal generators are inexpensive oscillation circuits with crystal units. By configuring and adjusting the value of the capacitor for adjustment in the oscillation circuit so that the oscillation frequency of the reference signal generator of the dependent station (slave unit) and the control station matches, the radio communication frequency of the control station and the dependent station It was possible to suppress the deterioration of the reception quality due to the shift.

  On the other hand, in the case of a wireless communication system in which a control station (public base station) and a dependent station (PHS terminal) cannot be adjusted at the same time as in PHS, both of them can be adjusted without simultaneously adjusting the oscillation frequency of each reference signal generator. Each reference signal generator uses a crystal oscillator with a temperature compensation circuit that has a small deviation from the nominal frequency and a small frequency deviation due to a temperature change with a stable oscillation frequency. It was expensive. When making a dual-purpose handset that can be used by both the cordless telephone master unit and the wireless doorphone master unit, the cordless telephone master unit, the wireless doorphone master unit, and the dual-purpose handset also suppress deterioration in reception quality due to a shift in radio communication frequency. Therefore, an expensive reference signal generator used in a wireless communication system such as PHS is required. Therefore, in a wireless communication system in which a dependent station communicates with a plurality of control stations, an expensive reference signal generator is required in order to suppress deterioration in wireless communication quality due to an error in each communication frequency. The problem was that the price would be high.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an inexpensive wireless communication system that does not require an expensive reference signal generator and a method for adjusting the communication frequency of the wireless communication system.

The main feature of the present invention is that the control station receives a radio signal transmitted from another radio communication system and adjusts a communication frequency for radio communication based on the received radio signal.

The wireless communication system of the present invention receives a wireless signal transmitted from another wireless communication system, and adjusts a communication frequency for wireless communication based on the received wireless signal, thereby generating an expensive reference signal for generating a high frequency. There is an advantage that it is possible to provide a low-cost wireless communication system in which deterioration of wireless quality due to a shift in communication frequency is suppressed, and a method for adjusting the communication frequency of the wireless communication system.

An object of the present invention is to receive a radio signal transmitted from another radio communication system and to perform radio communication based on the received radio signal in order to suppress degradation of radio communication quality due to an error in communication frequency with a low-cost circuit configuration. It was realized by adjusting the communication frequency for

An embodiment of the present invention is a radio communication system including a control station and at least one subordinate station capable of communicating with the control station, and the control station transmits a TDMA (TDMA) transmitted from another radio communication system. (Time Division Multiplex) radio signal is received, and a communication frequency for TDMA radio communication with a dependent station is adjusted based on the received radio signal.

The control station also generates an oscillation circuit that generates a reference signal, and a radio unit that generates a radio signal for radio communication based on the reference signal of the oscillation unit, generates a radio signal using the radio frequency signal, and transmits and receives the radio signal A frame processing unit that measures time based on the reference signal of the oscillation unit, an oscillation frequency adjustment unit that adjusts the frequency of the reference signal generated by the oscillation unit, and a control unit that controls the entire control station The control station receives a control signal transmitted by another wireless communication system, measures the reception interval of the control signal received by the frame processing unit, and if the reception interval is longer than a predetermined time, When the oscillation frequency is increased and the reception interval of the received control signal is shorter than a predetermined time, control is performed to decrease the oscillation frequency of the reference signal.

  According to this configuration, the control station corrects the deviation of the high-frequency signal for communication with the subordinate station based on the received signal from the wireless communication system on which the control station is a reference, thereby reducing the low-cost reference signal generator. It is possible to provide a wireless communication system that suppresses deterioration of wireless communication quality due to a shift in communication frequency with the circuit configuration used.

  In another embodiment of the present invention, the dependent station receives a radio signal transmitted by another radio communication system or a radio signal transmitted by the control station, and based on the received radio signal, The radio signal transmitted by the control station and the radio signal transmitted by the other radio communication system operate so that the frequency accuracy of the radio signal to be transmitted matches the frequency accuracy of the radio signal transmitted by another radio communication system or the control station. When receiving a signal, based on a radio signal transmitted by another radio communication system, the frequency accuracy of the radio signal transmitted by itself is matched with the frequency accuracy of the radio signal transmitted by the other radio communication system. It is a thing.

  In addition, the dependent station includes an oscillation circuit that generates a reference signal, and a radio unit that generates a high-frequency signal for wireless communication based on the reference signal of the oscillation unit, generates a radio signal using the high-frequency signal, and transmits and receives the radio signal A frame processing unit that measures time based on the reference signal of the oscillation unit, an oscillation frequency adjustment unit that adjusts the frequency of the reference signal generated by the oscillation unit, and a control unit that controls the entire dependent station The dependent station receives a control signal transmitted from another radio communication system or control station, and sets a reception interval of each radio signal transmitted from the other radio communication system or control station by the frame processing unit. Measure, if the reception interval is longer than the predetermined time, increase the oscillation frequency of the reference signal, and if the reception interval of the received control signal is shorter than the predetermined time, the reference signal It is obtained so as to control to decrease the oscillation frequency.

  According to this configuration, there is an advantage that it is possible to provide a wireless communication system in which deterioration of wireless communication quality due to a shift in communication frequency is suppressed with a circuit configuration using a low-cost reference signal generator.

  In another embodiment of the present invention, a second sub-station capable of communicating with the first control station, the second sub-station, and the second control station can communicate with the first control station and the first control station. The second control station receives a radio signal transmitted by the first control station, and based on the received radio signal, the frequency accuracy of the radio signal transmitted by itself In accordance with the frequency accuracy of the radio signal transmitted by the first control station, the first dependent station receives the radio signal transmitted by the first control station, and based on the received radio signal, The second subordinate station receives the radio signal transmitted from the second control station, and operates so that the frequency accuracy of the radio signal transmitted by itself matches the frequency accuracy of the radio signal transmitted by the first control station. Based on the received radio signal, the frequency accuracy of the radio signal transmitted by itself is Control station is that with aligning the frequency accuracy of the radio signal to be transmitted.

  In addition, at least one of the first dependent station and the second dependent station generates a high-frequency signal for wireless communication based on the oscillation circuit that generates the reference signal and the reference signal of the oscillating means, and wirelessly uses the high-frequency signal. A radio unit that generates a signal and transmits / receives a radio signal, a frame processing unit that measures time based on a reference signal of the oscillation unit, an oscillation frequency adjustment unit that adjusts the frequency of the reference signal generated by the oscillation unit, A control unit that controls the entire dependent station, wherein the first dependent station and the second dependent station receive a control signal transmitted from each control station to which the subordinate station belongs, and the frame processing unit receives the control signal from each control station to which the subordinate station belongs. When the reception interval of the transmitted radio signal is measured and the reception interval is longer than the predetermined time, the oscillation frequency of the reference signal is increased, and the reception interval of the received control signal is shorter than the predetermined time Is the standard Of those which is adapted to control so as to reduce the oscillation frequency.

  With this configuration, when the dependent station receives the transmission signals of both the first control station and the second control station, it operates to match the frequency of the radio signal based on the reception of the first control station. Therefore, from the second control station that is adjusting the frequency of the radio signal based on the received signal of the first control station, that is, from the control station having a large frequency deviation from the first control station. The advantage that the frequency of the radio signal is not corrected with the received signal, there is no risk of a frequency shift due to the influence of the second control station, and deterioration of communication quality due to the frequency shift can be reduced. Have

  In addition, when the dependent station can only receive one of the control stations, it operates to match the frequency of the radio signal based on the received signal of the control station that can be received. Even in a state where it cannot be performed, there is an advantage that it is possible to reduce deterioration in communication quality due to a frequency shift in communication with a control station that is receiving.

  Further, the dependent station generates a high frequency for wireless communication based on one reference signal, receives a control signal transmitted from the first control station or the second control station, and receives the received control signal. Based on the interval, the oscillation frequency of the reference signal is adjusted, a high frequency signal for wireless communication is generated using the reference signal, and the frequency of the wireless communication between the dependent station and the first control station or the second control station By reducing the difference between the high frequency signals of the first control station or the second control station and the dependent station, the control station and the dependent station can be reduced with a circuit configuration using a low-cost reference signal generator. There is an advantage that it is possible to provide a wireless communication system in which deterioration of wireless communication quality due to a high-frequency signal shift between them is suppressed.

  The second control station receives the control signal transmitted from the first control station, adjusts the oscillation frequency of the reference signal based on the received control signal, and uses the reference signal to generate a high frequency for wireless communication. The first dependent station and the second dependent station receive the control signal transmitted by the control station to which the signal belongs, adjust the oscillation frequency of the reference signal based on the received control signal, and By using the signal to generate a high-frequency signal for wireless communication and reducing the frequency deviation of the wireless communication between the control station and the slave station that can communicate with the control station, the circuit configuration using a low-cost reference signal generator There is an advantage that it is possible to provide a wireless communication system in which deterioration of wireless communication quality due to a shift of a high-frequency signal between a control station and a dependent station is suppressed.

  The second control station receives the control signal transmitted from the first control station, adjusts the oscillation frequency of the reference signal based on the reception interval of the received control signal, and performs wireless communication using the reference signal. The first dependent station and the second dependent station receive the control signal transmitted by the control station to which each belongs, and oscillate the reference signal based on the reception interval of the received control signal. Low-frequency reference signal generation by adjusting the frequency, generating a high-frequency signal for wireless communication using the reference signal, and reducing the frequency shift of the wireless communication between the control station and the dependent station that can communicate with the control station This has the advantage that it is possible to provide a wireless communication system that suppresses deterioration of wireless communication quality due to a high-frequency signal shift between a control station and a subordinate station with a circuit configuration using a device.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of the door phone master unit of the present invention.

  FIG. 2 is a block diagram of the cordless telephone master of the present invention.

  FIG. 3 is a block diagram of the dual-purpose handset of the present invention.

  In FIG. 1, reference numeral 100 denotes a wireless doorphone main unit main body that operates as a second control station, and reference numeral 190 denotes an entrance terminal connected to the wireless doorphone main unit main body 100. In the radio doorphone main unit 100, 101 is an antenna for inputting and outputting radio signals, 110 is a part of a radio unit, and a transmission unit that converts a transmission signal such as a control signal and an audio signal into a radio signal and outputs it, 120 is a part of the radio unit that receives and demodulates a radio signal, 130 is a part of the radio unit and generates a high-frequency signal for radio communication, and 140 is an oscillating means. An oscillation circuit that generates a reference signal used to generate a high-frequency signal in the unit 130, 150 is an oscillation frequency adjustment means, and an oscillation frequency adjustment unit for adjusting the oscillation frequency of the reference signal generated by the oscillation circuit, Reference numeral 160 denotes a frequency divider that divides the reference signal generated by the oscillation circuit 140 to generate a bit clock for reception processing. Reference numeral 170 denotes time measuring means. The transmission data is output with the bit synchronization preamble, frame synchronization sync word, and error detection CRC added, and the frame synchronization sync word is detected from the demodulated output and received. A frame processing unit 180 that separates data and CRC for error detection, determines whether there is a reception error, and outputs correctly received data. 180 converts an image signal transmitted from the front door unit 190 into digital image data. An image processing unit 181 that converts the audio signal transmitted from the front door unit 190 into digital audio data, and converts the audio data received and demodulated as a radio signal into an analog audio signal. , 182 separates the image signal, the audio signal, and the control signal from the signal transmitted from the entrance cordless handset 190, and outputs the voice signal to the entrance cordless handset. That the entrance door station interface, 189 is a control means is a control unit for controlling the entire wireless indoor apparatus main body 100. Further, in the front door unit 190, reference numeral 191 denotes a door phone base unit interface for multiplexing and outputting image signals, sound signals, and control signals transmitted from the front hand unit 190 and inputting sound signals from the wireless doorphone main unit body 100. , 192 is a camera unit that captures an image and generates an image signal, 193 is a microphone that inputs an audio signal, 194 is a speaker that outputs the audio signal, and 195 is an operation unit for performing a visitor notification.

  In FIG. 2, 200 is a cordless telephone base unit that operates as a first control station, 201 is an antenna for inputting and outputting radio signals, 210 is a part of a radio unit, and is used for control signals, audio signals, etc. A transmission unit 220 that converts a transmission signal into a radio signal and outputs it, 220 is a part of the radio unit, and a reception unit that receives and demodulates the radio signal, and 230 is a part of the radio unit, and a high-frequency signal for radio communication The synthesizer unit 240 generates the reference signal used to generate the high-frequency signal in the synthesizer unit 230. The oscillation circuit 260 divides the reference signal generated by the oscillation circuit 240. A frequency divider for generating a bit clock for reception processing, 270 is a time division multiplexing control means, managing the timing of the frame and slot, while transmitting the bit synchronization preamble to the transmission data, Frame sync sync word and error detection CRC are added and output. Also, frame sync sync word is detected from the demodulated output, and received data and error detection CRC are separated to check for reception errors. A frame processing unit 281 that determines and outputs the received data correctly received, converts the audio signal input from the telephone line side into digital audio data, and also converts the audio data received and demodulated as a radio signal into analog data A voice processing unit 282 for converting the voice signal into a voice signal, a telephone line interface 282 for inputting / outputting voice signals to / from the telephone line, and a control unit 289 for controlling the entirety of the cordless telephone master 200.

  In FIG. 3, reference numeral 300 denotes a dual-purpose slave that operates as a slave station that can communicate with the radio doorphone master unit 100 and the cordless telephone master unit 200, 301 is an antenna that inputs and outputs radio signals, and 310 is a radio unit. A transmission unit that converts a transmission signal such as a control signal or a voice signal that is a part of the radio signal into a radio signal and outputs the radio signal; 320 a reception unit that receives and demodulates a radio signal that is a part of the radio unit; and 330 a radio unit , A synthesizer unit for generating a high-frequency signal for wireless communication, 340 is an oscillating means, an oscillation circuit for generating a reference signal used for generating a high-frequency signal in the synthesizer unit 330, and 350 is an oscillation frequency An oscillation frequency adjusting unit 360 that adjusts the oscillation frequency of the reference signal generated by the oscillation circuit as an adjustment unit, divides the reference signal generated by the oscillation circuit 340 and performs reception processing. A frequency divider 370 that generates a bit clock is a clocking unit that adds a bit synchronization preamble, a frame synchronization sync word, and an error detection CRC to transmission data while managing the timing of frames and slots. A frame processing unit that detects a sync word for frame synchronization from the demodulated output, separates CRC for reception data and error detection, determines the presence or absence of reception error, and outputs received data correctly received; Reference numeral 380 denotes an image processing unit that performs processing for displaying image data transmitted from the wireless doorphone main unit 100. Reference numeral 381 converts an audio signal for transmission into digital audio data and receives the signal as a radio signal. An audio processing unit that converts the demodulated audio data into an analog audio signal, 382 received from the wireless doorphone main unit 100 A display unit for displaying an image, a telephone number, and the like; 383, a microphone for inputting an audio signal; 384, a speaker for outputting an audio signal; 385, an operation unit for performing response operation, transmission, input of a telephone number, and the like; Reference numeral 389 denotes a control unit that controls the entire dual-purpose slave unit 300.

  FIG. 4 is an explanatory diagram of the time division multiplex frame slot of the present invention. When one frame is divided into eight slots and time division multiplex communication is performed, the frame, slot configuration, and each slot are shown. The example of a structure of the data sequence transmitted / received is shown. The data string of each slot includes a ramp bit (referred to as R1 in FIG. 4) for the rising edge of the radio signal, a preamble composed of repetition of 1 and 0 data for bit synchronization, and frame synchronization. Sync word composed of a data string of a specific pattern, control data, audio data, transmission data for transmitting image data, CRC for error detection, ramp bit for falling edge of radio signal (denoted as R2 in FIG. 4) , Each of the slots is composed of a guard that is a transmission prohibition period for preventing the communication signals between the slots from overlapping due to the influence of the propagation delay, and a predetermined bit length is assigned to each guard.

  Next, the operation will be described with reference to the drawings.

First. The operation of the cordless telephone base unit 200 will be described.
The radio doorphone main unit 100 and the cordless telephone base unit 200 operate as a control station, and transmit a control signal for a frame including the identification ID of the local station and a signal for slot synchronization in a specific slot in the frame. The slave unit 300 operating as a dependent station receives the control signals of the radio doorphone main unit 100 and the cordless telephone base unit 200 in synchronization with the control signal, and synchronizes time-division multiplexed frames and slots with the control station. At the same time, it prepares for a call from the control station such as a visitor notification from the wireless doorphone main unit main body 100 and an external line incoming notification of a cordless telephone.

  In order to transmit the control signal, the cordless telephone base unit 200 first determines the frame and slot timing for time division multiplexing. That is, the reference signal generated by the oscillation circuit 240 is divided by the frequency divider 260 to generate a bit clock equal to the time for transmitting 1-bit data, and the frame processor 270 performs time division based on the bit clock. Frame and slot timings for multiplexing are generated, and the control unit 289 is notified of the frame and slot timings. Then, the control unit 289 selects one of the slots as a control signal transmission slot, and the synth unit 230 generates a transmission frequency for transmitting the control signal in accordance with the timing of the transmission slot of the selected control signal. Then, the transmission unit 210 is activated, and the identification ID of the own station, which is transmission data of the control signal, is output to the frame processing unit 270. The frame processing unit 270 outputs a transmission data sequence in which a preamble, a sync word, and a CRC are added to the transmission data to the synthesizer unit 230. In the synthesizer 230, based on the reference signal generated by the oscillation circuit 240, the transmission data string (modulation) input from the frame processor 270 having the transmission frequency for control signal transmission notified from the controller 289 as the center frequency. A high-frequency signal that is frequency-modulated according to the signal) is generated, amplified by the transmitter 210 to a prescribed output, and a control signal is transmitted from the antenna 201.

  Next, the standby operation of the cordless telephone master device 200 will be described. The cordless telephone base unit 200 that operates as a control station transmits a control signal as described above, and receives a communication request transmitted from the dual-purpose slave unit 300 that is a subordinate station. Reception is performed in a slot in a predetermined inter-position system. That is, based on the timing of the frame and slot notified from the frame processing unit 270, the control unit 289 and a slot transmitting a control signal and a slot in a predetermined inter-position system (hereinafter referred to as a standby slot) The synthesizer 230 is set to generate a high-frequency signal for receiving a communication request from the slave station (shared slave device 300), and the receiver 220 is activated. The synthesizer 230 operates to generate a high-frequency signal having a set frequency from a reference signal source input from the oscillation circuit 240, and the receiver 220 performs reception demodulation using the high-frequency signal input from the synthesizer 230. Start the action to do. In this standby slot, when a radio signal is input from the antenna 301 and input to the receiving unit 320, the received radio signal is demodulated and a demodulated data string is output to the frame processing unit 370. The frame processing unit 370 detects a sync word from the demodulated data string, separates the received data and the CRC, determines whether or not the reception is normal, and if the reception is normal, the reception data (the transmission data portion of FIG. 4). Is output to the control unit 389. The control unit 389 analyzes the received data, and when it is a communication request from the dual-purpose slave unit 300, starts control to start bidirectional communication with the dual-purpose slave unit.

  Next, a description will be given of the communication state between the cordless telephone master unit 200 and the dependent station (combined slave unit 300). When responding to an incoming call from the outside line in the dual-purpose handset 300 or when sending to the external line, the double-purpose handset 300 establishes a two-way wireless link for voice communication, so that the cordless telephone master unit described above is established. A communication request is transmitted in 200 standby slots. When receiving the communication request from the dual-purpose handset 300, the control unit 289 of the cordless telephone base unit 200 selects a two-way communication slot and communication frequency, and selects the slot selected in the slot transmitting the control signal. In addition to notifying the slave frequency unit 300 of the communication frequency, the synth unit 230, the transmission unit 210, and the reception unit are matched with the timing of the selected communication slot based on the timing of the frame and slot notified from the frame processing unit 270. 220 is started. The synthesizer 230 generates a modulated wave for transmission and a high-frequency signal for reception based on the reference signal generated by the oscillation circuit 240, and performs wireless communication for bidirectional voice communication with the dual-purpose slave unit. To do. The audio data received and demodulated from the dual-purpose slave is separated by the frame processing unit 270 based only on the sync word, and is output to the audio processing unit 281. The audio processing unit 281 outputs an analog audio signal. And output to the telephone line via the telephone line interface 282. The voice signal input from the telephone line via the telephone line interface 282 is converted into voice data of a digital signal by the voice processing unit 281, and a preamble, sync word, CRC, etc. are added by the frame processing unit 270, In accordance with the timing of the transmission slot of the two-way communication slot, the modulated wave of the slot for transmitting voice data is generated by outputting to the synth unit 230, amplified by the transmission unit 210 to the specified output, and transmitted.

  The operation of generating a high-frequency signal for transmission / reception based on the reference signal generated by the oscillating circuit 240 by the synthesizer 230 is generated by the oscillating circuit 140 in the synthesizing unit 130 of the wireless doorphone main unit 100 described later. This is the same as the operation of generating a high-frequency signal for transmission / reception based on the reference signal, and the description is omitted here.

  Next, the operation of the wireless doorphone main unit 100 will be described.

  First, the control signal transmission operation of the wireless doorphone main unit 100 will be described. When transmitting the control signal, the wireless doorphone main unit 100 receives the control signal transmitted from the cordless telephone base unit 200 so that the error between the nominal frequency and the actual communication frequency is the same as that of the cordless telephone base unit 200. The frequency of the reference signal for generating a high frequency for wireless communication is adjusted. In order to receive the control signal of the cordless telephone base unit 200, the control unit 189 sets the synthesizer unit 130 to generate a high-frequency signal for receiving the control signal of the cordless telephone base unit, and sets the receiving unit 120 in the continuous reception state. To. When the control signal of cordless telephone base unit 200 is input from antenna 101 to receiving section 120, the received radio signal is demodulated and a demodulated data string is output to frame processing section 170. The frame processing unit 170 detects a sync word from the demodulated data sequence, separates the received data and the CRC, determines whether or not the reception is normal, and in the case of normal reception, the received data (transmission data portion in FIG. 4). Is output to the control unit 189. Based on the identification ID of the transmitting station included in the received data, the control unit 189 determines whether the received data is a control signal transmitted from a cordless telephone master unit that performs frequency synchronization, and controls the cordless telephone parent that performs frequency synchronization. If the control signal is transmitted from the machine, the control is switched so as to be received in accordance with the timing of the received control signal.

  Next, the operation when radio doorphone main unit main body 100 performs reception in accordance with the transmission timing of the control signal of cordless telephone main unit 200 will be described. The radio doorphone main unit 100 is a time measured based on the reference signal generated by the oscillation circuit 140, and based on the reception timing of the control signal of the cordless telephone base unit 200 received by continuous reception, The transmission timing of the control signal of the telephone base unit 200 is obtained, and thereafter, control is performed so as to be received at every transmission timing of the control signal of the cordless telephone base unit 200. In other words, the reference signal generated by the oscillation circuit 140 is divided by the frequency divider 160 to generate a bit clock equal to the time for receiving 1-bit data, and the frame processing unit 170 generates the bit clock. Measures the elapsed time from the reception timing of the sync word of the control signal of the cordless telephone base unit 200 received last time using the received bit clock, notifies the control unit 189 of the arrival of the preparation timing of reception of the control signal, and performs control. In the unit 189, the timing corresponding to the transmission slot of the control signal of the cordless telephone master unit 200 is determined based on the arrival timing of the control signal reception preparation timing of the cordless telephone base unit 200 notified from the frame processing unit 170. In order to receive the slot, the synth unit 130 receives a control signal for receiving the control signal of the cordless telephone base unit 200. Configured to generate a wave signal, it activates the receiving unit 120. Then, the receiving unit 120 receives the control signal of the cordless telephone base unit 200, and the demodulated data is output to the frame processing unit 170. The frame processing unit 170 reads the demodulated data output from the receiving unit 120 one bit at a time in synchronization with the bit clock output from the frequency divider 160, searches the demodulated data for a data string that matches the sync word, When a word is detected, the elapsed time from the previously received sync word (the number of bits, that is, the number of clocks of the bit clock output from the divider 160) is determined by the frame period of the cordless telephone base unit 200 (the total number of bits of one frame). ), The control unit 189 is notified of a shift in the reception cycle, which is the same (long) (long) or short (small), and based on the reception timing of the newly received sync word, The timing of the arrival of the preparation timing for receiving the control signal is started. On the other hand, when the reception of the reception cycle is notified from the frame processing unit 170, the control unit 189 determines that the sync word detection cycle of the control signal of the cordless telephone base unit 200 timed by the frame processing unit 170 is the cordless telephone base unit. When it was longer (more) than the 200 predetermined frame period (total number of bits in one frame), the oscillation frequency adjustment unit 150 was controlled to reduce the frequency of the reference signal generated by the oscillation circuit 140, and was shorter ( If not, the oscillation frequency adjustment unit 150 is controlled to increase the frequency of the reference signal generated by the oscillation circuit 140.

  Next, the operations of the synth unit 130, the oscillation circuit 140, and the oscillation frequency adjustment unit 150 of the wireless doorphone main unit 100 will be described with reference to FIG. FIG. 5 is a block diagram of the oscillation frequency adjustment unit of the present invention.

  In FIG. 5, reference numeral 131 of the synthesizer unit 130 corresponds to a control voltage applied to a control terminal (denoted as CNT in FIG. 5) and a modulation signal input from a modulation terminal (denoted as MOD in FIG. 5). A voltage-controlled oscillator that outputs an unmodulated high-frequency signal having an oscillation frequency corresponding to the control voltage, or a high-frequency signal that is frequency-modulated according to the modulation signal at a center frequency corresponding to the control voltage, 132 is a voltage-controlled oscillator 130 A variable frequency divider that divides the high-frequency signal according to a value set by the control unit 189, a fixed frequency divider that divides the reference signal output from the oscillation circuit 140 by a predetermined value, Reference numeral 134 denotes a phase comparator that outputs a phase difference signal corresponding to the phase difference between the frequency-divided outputs of the variable frequency divider 132 and the fixed frequency divider 133, and 135 denotes a response of the synth unit 130 while smoothing the phase difference signal. Speed In the oscillation circuit 140, 141 is a crystal oscillator for oscillation, 142 is an amplifier for oscillation, and 143 and 144 are for oscillation. Capacitors 145 are output buffer amplifiers, and oscillation frequency adjusting unit 150, 151, 152 and 153 are oscillation frequency adjusting capacitors, and 155, 156 and 157 are switching signals from the control unit. Accordingly, the switch 151 switches whether or not the capacitors 151, 152, and 153 for adjusting the oscillation frequency are connected in parallel to the capacitor 144 of the oscillation circuit 140.

  Next, operations of the synth unit 130, the oscillation circuit 140, and the oscillation frequency adjustment unit 150 configured as described above will be described.

First, the operation of the synth unit 130 will be described. In this description, the operation when a voltage-controlled oscillator having the characteristic that the oscillation frequency of the high-frequency signal generated by the voltage-controlled oscillator 131 increases as the voltage applied to the control terminal of the voltage-controlled oscillator 131 increases is described. An example will be described. The voltage controlled oscillator 131 generates a high frequency signal having a frequency according to the voltage input to the control terminal. The high-frequency signal generated by the voltage-controlled oscillator 131 is output as a high-frequency signal for wireless communication to the transmission unit and the reception unit, and is also output to the variable frequency divider 132. The variable frequency divider from the control unit 189 The frequency is divided by a frequency division number corresponding to the set communication frequency of the wireless communication and input to the phase comparator 134. On the other hand, the reference signal input from the oscillation circuit 140 that generates the reference signal is frequency-divided by a predetermined value by the fixed frequency divider 133 and input to the phase comparator 134. The phase comparator 134 compares the signal input from the variable frequency divider 132 with the signal input from the fixed frequency divider 133, and determines the signal input from the variable frequency divider 132 according to the phase difference between the two. When the phase is advanced, the signal input from the fixed frequency divider 133 from the rising edge of the signal input from the variable frequency divider 132 so as to reduce the oscillation frequency of the high frequency signal generated by the voltage controlled oscillator 131. When the phase of the signal input from the variable frequency divider 132 is delayed during the period up to the rising edge of the signal, the oscillation frequency of the high frequency signal generated by the voltage controlled oscillator 131 is increased. A period from the rising edge of the signal input from the fixed frequency divider 133 to the rising edge of the signal input from the variable fixed frequency divider 132, Hi Outputs h level of the voltage, also operates so that the output becomes high impedance in other segments. The signal output from the phase comparator 134 is smoothed by the loop filter 135 and input to the control terminal of the voltage controlled oscillator 131. For example, when the initial voltage input to the control terminal of the voltage controlled oscillator 131 is Vc, when a low level pulse is output from the phase comparator 134, the charge charged in the capacitor in the loop filter 135 is charged. Is discharged, the output voltage becomes lower than Vc, the oscillation frequency of the high frequency signal generated by the voltage controlled oscillator 131 decreases, and a high level pulse is output from the phase comparator 134, the capacitor in the loop filter 135 is output. In the state where the output voltage is higher than Vc, the oscillation frequency of the high frequency signal generated by the voltage controlled oscillator 131 is increased, and the output of the phase comparator 134 is high impedance, Charge is held in the capacitor, and the output voltage is held at Vc. Oscillation frequency of the high frequency signal generated by the vessel 131 is maintained. Therefore, in a state where the output phases of the variable frequency divider 132 and the fixed frequency divider 133 match, the frequency of the reference signal input to the fixed frequency divider 133 is fs, the frequency division number of the fixed frequency divider is N, When the frequency division number of the variable frequency divider 132 is M, the oscillation frequency of the voltage controlled oscillator 131 is fc:
fc = fs × M / N
Thus, the frequency is M / N times the oscillation frequency of the reference signal.

  Next, operations of the oscillation circuit 140 and the oscillation frequency adjustment circuit 150 will be described. The oscillation circuit 140 generates an oscillation signal by using the negative resistance of the amplifier 142, the inductance of the crystal oscillator 141, and the capacitance of each capacitor, and the oscillation frequency thereof includes an inductance component and a capacitance component of the crystal oscillator 141, The capacitance components of the capacitors 143, 144, 151, 152, and 153 are determined as main factors (capacitor leakage current and parasitic capacitance of the amplifier are ignored here). Accordingly, the oscillation frequency can be changed by opening and closing the switches 155, 156, and 157 and changing the combined capacitance components of the capacitors 143, 144, 151, 152, and 153. Note that the capacitance values of the capacitors 151, 152, and 153 do not need to be the same. For example, by setting the capacitance of each capacitor to the capacitor 151 = 1p, the capacitor 151 = 2p, and the capacitor 151 = 4p, the switches 155, 156 157, the combined capacity of the oscillation frequency adjustment circuit 150 can be adjusted to 8 levels, 0p, 1p, 2p,... 7p, and the oscillation frequency of the reference signal generated by the oscillation circuit 140 can be adjusted. When it is desired to reduce the increment or increase the adjustment range, it is possible to obtain the desired oscillation frequency increment or adjustment range of the reference signal by increasing the number of capacitors and switches of the oscillation frequency adjustment unit 150. . In addition, the opening / closing of the switches 155, 156, and 157 is controlled by the control unit 189, and the control unit 189 determines that the sync word detection cycle of the control signal of the cordless telephone master unit 200 timed by the frame processing unit 170 is cordless telephone. When the frame period (total number of bits of one frame) of the base unit 200 is longer (more), the switches 155 and 156 of the oscillation frequency adjustment unit 150 are set so as to reduce the frequency of the reference signal generated by the oscillation circuit 140. 157 is switched from the current open / closed state to increase the combined capacity, and when it is short (less), the switches 155, 156 of the oscillation frequency adjusting unit 150 are increased so as to increase the frequency of the reference signal generated by the oscillation circuit 140. 157 is switched from the current open / close state to increase the combined capacity.

  Next, the control signal transmission operation of the wireless doorphone main unit 100 will be described. The wireless doorphone main unit 100 operates as a control station, and transmits a control signal for frame and slot synchronization including an identification ID and the like in a section where a control signal from the cordless telephone base unit 200 is not received. . That is, the wireless doorphone main unit main body 100 supplements the control signal of the cordless telephone base unit 200 by continuous reception, and after switching the operation to perform reception in accordance with the transmission timing of the control signal of the cordless telephone base unit 200, Following the reception of the control signal of cordless telephone base unit 200, control unit 189 switches the operation to perform reception in accordance with the transmission timing of the control signal of cordless telephone base unit 200. After that, control is performed to switch the frame processing unit 170 to the time division transmission / reception mode. The frame processing unit 170 determines the timing of the frame and slot of the time division multiplexing communication of the local station so that the transmission period of the control signal of the local station does not overlap the reception period of the control signal of the cordless telephone base unit 200, and the control unit 189 Is notified of the arrival of the timing of preparation for transmission of the control signal of the own station. When notified of the arrival of the control signal transmission preparation timing, the control unit 189 sets the synthesizer unit 130 to generate a transmission frequency for transmitting the control signal, activates the transmission unit 110, and controls the frame processing unit 170. The identification ID of the own station, which is signal transmission data, is output. The frame processing unit 170 outputs a transmission data sequence in which a preamble, a sync word, and a CRC are added to the transmission data to the synthesizer unit 130. In the synthesizer unit 130, based on the reference signal generated by the oscillation circuit 140, a transmission data string (modulation) input from the frame processing unit 170 centered on the transmission frequency for control signal transmission notified from the control unit 189. A high-frequency signal frequency-modulated according to the signal) is generated, amplified to a prescribed output by the transmission unit 110, and a control signal is transmitted from the antenna 101.

  Next, an explanation will be given of the operation of notifying customers using doorphones. When the call button is pressed on the operation unit of the front door unit 190, the camera unit 192 starts capturing an image, and an image signal output from the camera unit 192 and a call button notification signal for notifying that the call button is pressed are displayed. It is superimposed on the doorphone master unit interface 191 and output to the radio doorphone master unit body 100. The entrance unit interface 182 separates the input image signal and the call button notification signal for notifying that the call button is pressed, and outputs the image signal to the image processing unit 180 and the call button notification signal to the control unit 189. . The image processing unit converts the image signal into digital image data and outputs the digital image data to the frame processing unit 170. On the other hand, the control unit 189 that has detected the call button notification signal performs control to transmit an incoming call notification for notifying a visitor and an image signal in the slot that has transmitted the control signal. That is, when notified of the arrival of the control signal transmission preparation timing, the control unit 189 sets the synthesizer unit 130 to generate a transmission frequency for control signal transmission, activates the transmission unit 110, and the frame processing unit 170. An incoming call notification control signal for notifying a visitor is output. In the frame processing unit 170, the incoming notification control signal from the control unit 189 and the image data from the image processing unit 180 are used as transmission data, and a transmission data sequence in which a preamble, a sync word, and CRC are added to the transmission data is synthesized. Output to. In the synthesizer unit 130, based on the reference signal generated by the oscillation circuit 140, a transmission data string (modulation) input from the frame processing unit 170 centered on the transmission frequency for control signal transmission notified from the control unit 189. A high-frequency signal frequency-modulated in accordance with the signal) is generated, amplified to a prescribed output by the transmission unit 110, and an incoming call notification control signal and image data are transmitted from the antenna 101.

  Next, the standby operation of the radio doorphone main unit 100 will be described. The radio intercom main unit 100 operating as a control station transmits a control signal as described above, and transmits a control signal in order to receive a communication request transmitted from the dual-purpose slave unit 300 that is a subordinate station. Reception is performed in a slot in a system between the slot and a predetermined position. That is, the frame processing unit 170 switched to the time division transmission / reception mode notifies the control unit 189 of the frame and slot timing of the time division multiplex communication of the local station, and the control unit 189 is notified from the frame processing unit 170. Based on the timing of the frame and the slot, the synth unit 130 is set to the dependent station (shared terminal) so that reception is performed in a slot in which a control signal is transmitted and a slot in a position system determined in advance (hereinafter referred to as a standby slot). The receiver 300 is set to generate a high-frequency signal for receiving a communication request from the device 300). The synthesizer 130 operates to generate a high-frequency signal having a set frequency from a reference signal source input from the oscillation circuit 140, and the receiving unit 120 performs reception demodulation using the high-frequency signal input from the synthesizer 130. Start the action to do. When a radio signal is input from the antenna 101 in this standby slot and input to the receiving unit 120, the received radio signal is demodulated and a demodulated data string is output to the frame processing unit 170. The frame processing unit 170 detects a sync word from the demodulated data sequence, separates the received data and the CRC, determines whether or not the reception is normal, and in the case of normal reception, the received data (transmission data portion in FIG. 4). Is output to the control unit 189. The control unit 189 analyzes the received data, and when it is a communication request from the dual-purpose slave unit 300, starts control to start bidirectional communication with the dual-purpose slave unit.

  Next, a description will be given of the communication state between the wireless doorphone main unit main body 100 and the slave station (shared slave unit 300). When the dual-purpose slave unit 300 responds to the visitor notification from the entrance slave unit 190, the dual-purpose slave unit 300 uses the standby slot of the wireless doorphone master unit main body 100 described above to establish a two-way wireless link for voice communication. Send a communication request. When receiving the communication request from the dual-purpose handset 300, the control unit 189 of the wireless intercom main unit 100 selects a bidirectional communication slot and communication frequency, and the slot selected by the slot transmitting the control signal. And the communication frequency to the slave unit 300, and based on the timing of the frame and slot notified from the frame processing unit 170, the timing of the selected communication slot is matched, and the synth unit 130, the transmission unit 110, and the reception The unit 120 is activated. The synthesizer unit 130 generates a modulated wave for transmission and a high-frequency signal for reception based on the reference signal generated by the oscillation circuit 140, and performs wireless communication for bidirectional voice communication with the dual-purpose slave unit. To do. The audio data received and demodulated from the dual-purpose slave is separated by the frame processing unit 170 based only on the sync word, and is output to the audio processing unit 181. The audio processing unit 181 outputs an analog audio signal. And is output to the entrance slave unit 190 via the entrance slave unit interface 182, and in the entrance slave unit 190, an audio signal input from the door phone master unit interface 191 is output from the speaker 194. In addition, the sound input from the microphone 193 is output to the wireless doorphone master unit main body 100 via the doorphone master unit interface 191, and the voice signal input from the entrance slave unit interface 182 in the wireless doorphone master unit main body 100 is The audio processing unit 181 converts the digital data into audio data, the frame processing unit 170 adds a preamble, sync word, CRC, and the like, and outputs to the synth unit 130 in accordance with the timing of the transmission slot of the bidirectional communication slot. Then, a modulated wave of a slot for transmitting audio data is generated, amplified to a prescribed output by the transmission unit 110, and transmitted.

  Next, the operation of the wireless doorphone main unit 100 when the control signal of the cordless telephone base unit 200 cannot be received will be described.

  As described above, in a situation where the control signal of the cordless telephone base unit 200 can be received, the doorphone base unit receives the control signal of the cordless telephone base unit 200 while receiving the control signal of the cordless telephone base unit 200 ( Based on the reception interval), it operates as a control station while adjusting the oscillation frequency of a reference signal that is a reference for generating frame and slot timing and generating a high-frequency signal for wireless communication. In a situation where the control signal of the device 200 cannot be received, the frame and slot timings are determined at a unique timing, and the control signal is transmitted, waited for, and bidirectionally communicated, as with the cordless telephone master device 200. That is, after starting the continuous reception for searching for the control signal of the cordless telephone master 200, the control unit 189 stops the continuous reception when the control signal of the cordless telephone master 200 cannot be received for a certain period of time. After controlling the frame processing unit 170 to operate in the independent mode, the frame processing unit 170 determines the timing of the frame and slot at its own timing in the same manner as the frame processing unit 270 of the cordless telephone master device 200, The operation is switched so as to notify the control unit 189 of the timing of the frame and the slot, and the wireless doorphone main unit 100 transmits the control signal, waits, and performs bidirectional communication at the unique timing generated by the frame processing unit 170. To do.

  Next, the operation of the dual-purpose slave unit 300 will be described.

  First, the operation when the dual-purpose slave unit 300 performs reception in accordance with the transmission timing of the control signal of the radio doorphone master unit 100 and the cordless telephone master unit 200 will be described.

  When receiving the control signal of the radio doorphone main unit 100 and the cordless telephone main unit 200, the dual-purpose sub unit 300 first searches for the control signal of the cordless telephone main unit 200 by continuous reception, and the control signal of the cordless telephone main unit 200. The control is switched so that reception is performed in accordance with the reception timing of the mobile phone, and then, in order to search for the control signal of the wireless doorphone main unit 100 in a section where the control signal of the cordless telephone base unit 200 is not received, the reception is continuously performed. When the control is performed and the control signal of the wireless doorphone main unit 100 is found, the operation shifts to the operation of receiving in accordance with the transmission timing of the control signals of the wireless doorphone main unit 100 and the cordless telephone main unit 200.

  When the power of the dual-purpose cordless handset 300 is turned on and the control unit 389 starts operating, the control unit 389 receives the control signal of the cordless phone base unit 200 in order to receive the control signal of the cordless phone base unit 200. It sets so that the high frequency signal for reception may be produced | generated, and makes the receiving part 320 the state of continuous reception. The synthesizer unit 330 operates to generate a high-frequency signal having a set frequency from a reference signal source input from the oscillation circuit 340, and the reception unit 320 performs reception demodulation using the high-frequency signal input from the synthesizer unit 330. Start the action to do. When the control signal of cordless telephone base unit 200 is input from antenna 301 to receiving section 320, the received radio signal is demodulated and a demodulated data string is output to frame processing section 370. The frame processing unit 370 detects a sync word from the demodulated data string, separates the received data and the CRC, determines whether or not the reception is normal, and if the reception is normal, the reception data (the transmission data portion of FIG. 4). Is output to the control unit 389. The control unit 389 determines whether the received data is a control signal transmitted from the cordless telephone base unit that is on standby based on the identification ID of the transmitting station included in the received data, and is transmitted from the cordless telephone base unit that is on standby. If it is a control signal, the control is switched so that the cordless telephone base unit 200 receives the signal in the corresponding slot in accordance with the timing of the received control signal.

  Next, the operation when dual-purpose slave unit 300 performs reception in accordance with the transmission timing of the control signal of cordless telephone master unit 200 will be described. The dual-purpose handset 300 is a time measured based on the reference signal generated by the oscillation circuit 340, and based on the reception timing of the control signal of the cordless telephone base unit 200 received by continuous reception, the next cordless telephone base The control signal transmission timing of the mobile phone 200 is obtained, and thereafter, control is performed so that reception is performed at every control signal transmission timing of the cordless telephone master device 200. That is, the reference signal generated by the oscillation circuit 340 is divided by the frequency divider 360 to generate a bit clock equal to the time for receiving 1-bit data, and the frame processing unit 370 generates the bit signal by the oscillation circuit 340. The elapsed time from the reception timing of the sync word of the control signal of the cordless telephone base unit 200 received last time is measured using the received bit clock, and the arrival of the preparation timing of reception of the control signal is notified to the control unit 389. In the unit 389, the timing corresponding to the transmission slot of the control signal of the cordless telephone master unit 200 is determined based on the arrival timing of the control signal reception preparation timing of the cordless telephone base unit 200 notified from the frame processing unit 370. In order to receive the slot, the synthesizer 330 receives a control signal for receiving the control signal of the cordless telephone base unit 200. Configured to generate a wave signal, it activates the receiving unit 320. The synthesizer 330 operates to generate a high-frequency signal having a frequency set as a reference signal source input from the oscillation circuit 340, and the reception unit 320 performs reception demodulation using the high-frequency signal input from the synthesizer 330. Do the action to do. Then, receiving unit 320 receives the control signal of cordless telephone base unit 200 and outputs demodulated data to frame processing unit 370. The frame processing unit 370 reads the demodulated data output from the receiving unit 320 one bit at a time in synchronization with the bit clock output from the frequency divider 360, searches the demodulated data for a data string that matches the sync word, When a word is detected, the elapsed time from the previously received sync word (the number of bits, that is, the number of bit clocks output from the frequency divider 360) is determined by the frame period of the cordless telephone base unit 200 (the total number of bits of one frame). The control unit 389 is notified of a difference in reception cycle, which is the same as (number), long (large), or short (small), and based on the reception timing of the newly received sync word, The timing of the arrival of the preparation timing for receiving the control signal is started.

  After the control is switched to perform reception in accordance with the transmission timing of the control signal of the cordless telephone base unit 200 as described above, the control unit 389 receives the transmission in accordance with the transmission timing of the control signal of the cordless telephone base unit 200. The control is started so as to receive the control signal of the wireless doorphone main unit 100 in a section other than the section in which the control signal of the cordless telephone base unit 200 is received while maintaining the control to perform the control. That is, when receiving the control signal of the cordless telephone base unit 200 to receive the control signal of the wireless doorphone main unit 100, the control unit 389 receives the control signal of the wireless doorphone main unit 100 from the synth unit 330. Is set to generate a high-frequency signal to be received, and the receiving unit 320 is set in a receiving state. The synthesizer 330 operates to generate a high-frequency signal having a frequency set based on the reference signal input from the oscillation circuit 340, and the reception unit 320 receives and demodulates using the high-frequency signal input from the synthesizer 330. The operation is performed. When the control signal of the wireless doorphone main unit 100 is input from the antenna 301 to the receiving unit 320, the received wireless signal is demodulated and a demodulated data string is output to the frame processing unit 370. The frame processing unit 370 detects a sync word from the demodulated data string, separates the received data and the CRC, determines whether or not the reception is normal, and if the reception is normal, the reception data (the transmission data portion of FIG. 4). Is output to the control unit 389. Control unit 389 determines, based on the identification ID of the transmitting station included in the received data, whether the received data is a control signal transmitted from radio doorphone main unit main body 100 that is on standby, and the radio doorphone main unit main body that is on standby If the control signal is transmitted from 100, the control is switched so that the radio doorphone main unit 100 is received in the corresponding slot in accordance with the timing of the received control signal.

  Next, the operation when the dual-purpose slave unit 300 performs reception in accordance with the transmission timing of the control signal of the radio doorphone master unit 100 and the cordless telephone master unit 200 will be described.

  As described above, when the control signal transmitted from the wireless doorphone main unit 100 is received while receiving the control signal of the cordless telephone main unit 200 in synchronization with the transmission timing of the control signal of the cordless telephone main unit 200, The device 300 is a time measured based on the reference signal generated by the oscillation circuit 340, and based on the received control signals of the wireless doorphone main unit 100 and the cordless telephone base unit 200, the next wireless Control signal transmission timings of doorphone main unit 100 and cordless telephone base unit 200 are obtained, and thereafter control is performed so as to be received at each transmission timing of control signals of wireless doorphone main unit 100 and cordless telephone base unit 200. That is, the reference signal generated by the oscillation circuit 340 is divided by the frequency divider 360 to generate a bit clock equal to the time for receiving 1-bit data, and the frame processing unit 370 generates the bit signal by the oscillation circuit 340. Measure the elapsed time from the reception timing of the sync word of the control signal of the wireless doorphone master unit 100 and the cordless phone master unit 200 received last time using the bit clock, and the wireless doorphone master unit 100 or the cordless phone master unit When the preparation timing for receiving the control signal 200 arrives, the control unit 389 notifies the control unit 389 that the preparation timing for receiving the control signal of the wireless doorphone master unit 100 or the cordless telephone master unit 200 has arrived. Control of radio doorphone main unit 100 or cordless telephone base unit 200 notified from frame processing unit 370 In order to receive the corresponding slot in accordance with the timing of the transmission slot of the control signal based on the arrival timing of the reception preparation timing of the signal, notification of the arrival of the preparation timing of reception of the control signal of the radio doorphone main unit 100 is given. If so, the synthesizer unit 330 is set to generate a high-frequency signal for receiving the control signal of the wireless doorphone main unit 100, and the arrival of the preparation timing for receiving the control signal of the cordless telephone base unit 200 is notified. If so, the synthesizer 330 is set to generate a high-frequency signal for receiving the control signal of the cordless telephone master 200, and the receiver 320 is activated. The synthesizer 330 operates to generate a high-frequency signal having a frequency set as the reference signal source input from the oscillation circuit 340, and the receiving unit 320 receives the high-frequency signal input from the synthesizer 330. An operation is performed to perform demodulation. Then, according to the setting of synthesizer 330 at receiver 320, the control signal of radio doorphone main unit 100 or cordless telephone master 200 is received, and the demodulated data is output to frame processor 370. The frame processing unit 370 reads the demodulated data output from the receiving unit 320 one bit at a time in synchronization with the bit clock output from the frequency divider 360, searches the demodulated data for a data string that matches the sync word, When a word is detected, when the control signal of the cordless telephone base unit 200 is received, the elapsed time (number of bits, that is, the number of clocks of the bit clock output from the frequency divider 360) from the previously received sync word is cordless. The control unit 389 is notified of a shift in the reception period that is the same as the frame period (total number of bits of one frame) of the telephone base unit 200, long (more), or shorter (small), and the newly received cordless telephone parent Based on the reception timing of the sync word of the device 200, the total timing of preparation for receiving the control signal of the next cordless telephone master device 200 is calculated. When the control signal of the wireless doorphone main unit 100 is received, the elapsed time from the sync word of the wireless doorphone main unit 100 received last time (the number of bits, that is, the bit clock output from the frequency divider 360) The control unit 389 is notified of a shift in the reception period, which is the same as the frame period (total number of bits of one frame) of the wireless doorphone main unit 100, long (large), or short (small). Based on the reception timing of the newly received sync word, the timing of the arrival of the preparation timing for receiving the control signal of the next wireless doorphone main unit 100 is started.

  Next, the operation of adjusting the oscillation frequency when the dual-purpose cordless handset 300 receives control signals for the wireless doorphone master unit 100 and the cordless telephone master unit 200 will be described.

  As described above, the frame processing 370 of the dual-purpose cordless handset 300 receives a shift in reception timing each time a control signal is received from the wireless doorphone main unit 100 and the cordless telephone base unit 200, that is, when each control signal is received. The shift of the bit position (number of bits from the previous reception) at the time of sync word detection is output to the control unit 389. The control unit 389 adjusts the oscillation frequency adjustment unit 350 so as to correct the deviation every time the deviation from the cordless telephone master device 200 is notified from the frame processing unit 370. That is, when the frame processing unit 370 is notified of the reception cycle shift of the cordless telephone master unit 200, the control unit 389 detects the sync word detection period of the control signal of the cordless telephone base unit 200 counted by the frame processing unit 370. Is longer (more) than the prescribed frame period (total number of bits of one frame) of the cordless telephone base unit 200, the oscillation frequency adjustment unit 350 is set to reduce the frequency of the reference signal generated by the oscillation circuit 340. If the control frequency is shorter (less), the oscillation frequency adjustment unit 350 is controlled to increase the frequency of the reference signal generated by the oscillation circuit 340.

  Further, in the standby state, when the dual-purpose handset 300 is receiving only the control signal of the wireless doorphone main unit 100, such as when it is set to wait only for the wireless doorphone main unit 100 according to the setting of the user, Instead of correcting the oscillation frequency based on the reception timing of the control signal of the cordless telephone base unit 200, the oscillation frequency is adjusted in accordance with the reception timing of the control signal of the wireless doorphone main unit body 100.

  The operation of adjusting the oscillation frequency is also performed in a bidirectional communication state with the wireless doorphone main unit 100 or the cordless telephone main unit 200 described later. In the case of bidirectional communication, the oscillation frequency is adjusted according to the reception timing of the reception slot of the bidirectional communication slot with the radio doorphone main unit 100, and the bidirectional communication with the cordless telephone main unit 200 is in progress. The oscillation frequency is adjusted according to the reception timing of the reception slot of the bidirectional communication slot with the cordless telephone base unit 200.

  Further, when the dual-purpose handset 300 can receive the control signal of the cordless telephone base unit 200 while performing bidirectional communication with the wireless doorphone base unit main body 100, the control signal of the cordless telephone base unit 200 is similar to the standby state described above. The oscillation frequency is adjusted according to the reception timing.

  The configuration of the synthesizing unit 330, the oscillation circuit 340, and the oscillation frequency adjusting unit 350 of the dual-purpose slave unit 300 is the same as that of the synthesizing unit 130, the oscillation circuit 140, and the oscillation frequency adjusting unit 150 of the wireless doorphone main unit 100 described above. The description of the method for adjusting the frequency of the reference signal generated by the oscillation circuit 300 in the dual-purpose slave unit 300 is omitted.

  FIG. 6 is an explanatory diagram of the operation in the standby state of the wireless communication system of the present invention.

  Next, the transmission state of the cordless telephone master unit 200 in the standby state, the transmission / reception of the control signal of the wireless doorphone main unit main body 100, and the transmission / reception state of the dual-purpose slave unit 300 will be described with reference to FIG.

  As shown in FIG. 6, the cordless telephone base unit 100 periodically transmits a control signal in the standby state (FIG. 6, hatched squares of the cordless telephone base unit). The intercom master unit 200 performs reception in accordance with the transmission timing of the cordless telephone base unit 100 (FIG. 6, the shaded squares of the door phone base unit), and the control signal is transmitted in the section where the cordless telephone base unit 100 is not receiving. Transmission is performed (FIG. 6, a black square of the door phone master unit). The dual-purpose handset 300 performs reception in accordance with the transmission timing of the cordless telephone base unit 100 (FIG. 6, shaded squares of the dual-purpose handset), and also performs reception in accordance with the transmission timing of the doorphone base unit 200 (see FIG. 6). 6. Black square of dual-purpose handset).

  In the state of FIG. 6, the intercom base unit 200 communicates by adjusting the oscillation frequency of the reference signal for transmitting and receiving the radio signal according to the reception interval of the control signal transmitted from the cordless telephone 100. While reducing the reception deterioration of the control signal of the cordless telephone base unit due to the frequency error, the error accuracy of the communication frequency of the control signal transmitted by itself is matched with the error precision of the communication frequency of the control signal transmitted by the cordless telephone base unit 100, Send control signals. Further, the dual-purpose handset adjusts the oscillation frequency of the reference signal for transmitting and receiving the radio signal according to the reception interval of the control signal transmitted from the cordless telephone 100. The dual handset 300 adjusts the oscillation frequency of the reference signal for transmission / reception of the radio signal based on the reception timing of the control signal transmitted from the cordless telephone 100, thereby controlling the cordless telephone base unit due to the communication frequency error. Reduce signal reception degradation. In addition, since the doorphone master unit transmits the control signal in accordance with the error accuracy of the cordless telephone master unit communication frequency, as a result, the communication frequency error when the dual-purpose slave unit receives the control control signal of the doorphone master unit. It is possible to reduce the reception degradation due to. In addition, when a radio signal is transmitted from the dual-purpose slave unit 300 to the cordless telephone master unit or the doorphone master unit, a wireless transmission signal generated by the dual-purpose slave unit 300 is a communication of a control signal transmitted by the cordless telephone master unit 100. Since it is generated using a reference signal adjusted in accordance with frequency error accuracy, reception degradation due to communication frequency error can be reduced in reception on the cordless telephone base unit or door phone base unit side.

  As described above, according to the radio communication system of the present invention, the accuracy of the communication frequency of the control signal of one control station serving as a reference is adjusted to the accuracy of the communication frequency of other control stations and dependent stations. Therefore, it is possible to provide a low-cost wireless communication system without requiring a highly accurate oscillation circuit in each wireless communication system.

  In addition, since the communication frequency adjustment method of the wireless communication system automatically adjusts the accuracy of the communication frequency in the communication state, the adjustment of the communication frequency at the time of manufacturing the wireless communication system is unnecessary, the productivity is improved, and the manufacturing cost is increased. Therefore, it is possible to provide a low-cost wireless communication system.

  When the second control station cannot receive the first control station, the second control station transmits a control signal at its own timing. When the dependent station receives only the second control station, the second control station receives the control signal from the second control station. Since the communication frequency is adjusted based on the reception timing of the transmitted control signal, even when there is no first control station, reception degradation due to a communication frequency error is reduced as in the case where the first control station is present. Even if the first control station stops operating due to a failure or the like, performance degradation does not occur.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. In the present embodiment, the cordless telephone master unit and the second control station are used as the first control station. As an example, one doorphone master unit and one slave unit as a dependent station have been described. However, a plurality of second control stations and slave stations may be provided. The wireless communication system of the present invention can be widely applied to wireless communication systems such as wireless LANs other than cordless telephones and wireless doorphones. Further, the present invention can be used even in the case where a plurality of the same radio equipment such as a plurality of cordless telephone master units are installed. In addition, the dependent station does not necessarily need to be capable of communicating with a plurality of control stations, and may be connectable to only one of the control stations.

  According to the present invention, a plurality of control stations and subordinate stations can automatically adjust a communication frequency shift by a simple circuit configuration and adjustment method, thereby suppressing deterioration in communication quality. This is suitable for a wireless communication system that performs division multiplexing.

Block diagram of doorphone master unit of the present invention Block diagram of the cordless telephone base unit of the present invention Block diagram of dual-use handset of the present invention Explanatory drawing of the time division multiplexing frame slot of this invention Block diagram of the oscillation frequency adjustment unit of the present invention Explanatory drawing of the operation | movement of the standby state of the radio | wireless communications system of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Radio doorphone main body 101 Antenna 110 Transmission part 120 Reception part 130 Synth part 140 Oscillation circuit 150 Oscillation frequency adjustment part 160 Frequency divider 170 Frame processing part 180 Image processing part 181 Audio | voice processing part 182 Entrance child machine interface 189 Control part 190 Entrance unit 191 Master unit interface 192 Camera unit 193 Microphone 194 Speaker 195 Operation unit

Claims (13)

A wireless communication system including a control station and at least one subordinate station capable of communicating with the control station, wherein the control station transmits a TDMA (Time Division Multiplex) radio transmitted from another wireless communication device A wireless communication system that receives a signal and adjusts a communication frequency for TDMA wireless communication with the dependent station based on the received wireless signal. The control station
An oscillation circuit for generating a reference signal;
A radio unit that generates a radio signal for radio communication based on a reference signal of the oscillation means, generates a radio signal using the radio frequency signal, and transmits and receives the radio signal;
A frame processing unit for measuring time based on a reference signal of the oscillation means;
An oscillation frequency adjusting unit that adjusts the frequency of the reference signal generated by the oscillation unit;
A control unit for controlling the entire control station,
The control station receives a control signal transmitted by the other wireless communication device, measures a reception interval of the control signal received by the frame processing unit, and if the reception interval is longer than a predetermined time, 2. The wireless communication system according to claim 1, wherein the oscillation frequency of the reference signal is controlled to be increased when the oscillation frequency of the signal is increased and the reception interval of the received control signal is shorter than a predetermined time. The dependent station receives a radio signal transmitted by the other radio communication device or a radio signal transmitted by the control station, and based on the received radio signal, the frequency accuracy of the radio signal transmitted by the subordinate station is increased. It operates to match the frequency accuracy of the radio signal transmitted by another radio communication device or the control station, and receives the radio signal transmitted by the other radio communication device and the radio signal transmitted by the control station. 3. The frequency accuracy of the radio signal transmitted by itself is matched with the frequency accuracy of the radio signal transmitted by the other radio communication device based on the radio signal transmitted by the other radio communication device. Wireless communication system. The dependent station is
An oscillation circuit for generating a reference signal;
A radio unit that generates a radio signal for radio communication based on a reference signal of the oscillation means, generates a radio signal using the radio frequency signal, and transmits and receives the radio signal;
A frame processing unit for measuring time based on a reference signal of the oscillation means;
An oscillation frequency adjusting unit that adjusts the frequency of the reference signal generated by the oscillation unit;
A control unit for controlling the entire dependent station,
Said dependent station, before Symbol another wireless communication device, or it receives a control signal which the control station transmits the frame preprocessing Symbol another wireless communication device by the unit, or transmitted from the control station radio Measure each signal reception interval, if the reception interval is longer than a predetermined time, increase the oscillation frequency of the reference signal, if the reception interval of the received control signal is shorter than the predetermined time, wireless communication system according to claim 1 for controlling so as to decrease the oscillation frequency of the reference signal. A wireless communication system comprising a first control station, a first dependent station capable of communicating with the first control station, a second control station, and a second dependent station capable of communicating with the second control station. And
The second control station receives the radio signal transmitted by the first control station, and the first control station transmits the frequency accuracy of the radio signal transmitted by itself based on the received radio signal. The first dependent station receives a radio signal transmitted by the first control station, and a radio signal transmitted by itself based on the received radio signal. The second subordinate station receives and receives the radio signal transmitted by the second control station, so that the frequency accuracy of the second control station matches the frequency accuracy of the radio signal transmitted by the first control station. A radio communication system that operates based on a radio signal so as to match the frequency accuracy of the radio signal transmitted by itself with the frequency accuracy of the radio signal transmitted by the second control station. At least one of the first dependent station and the second dependent station is:
An oscillation circuit for generating a reference signal;
A radio unit that generates a radio signal for radio communication based on the reference signal of the oscillation means, generates a radio signal using the radio frequency signal, and transmits and receives the radio signal;
A frame processing unit for measuring time based on a reference signal of the oscillation means;
An oscillation frequency adjusting unit that adjusts the frequency of the reference signal generated by the oscillation unit;
A control unit for controlling the entire dependent station,
Each of the first dependent station and the second dependent station receives a control signal transmitted from the control station to which each of the subordinate stations belongs, and sets a reception interval of radio signals transmitted from the respective control stations to which the frame processing unit belongs. Measure and increase the oscillation frequency of the reference signal if the reception interval is longer than the predetermined time. Decrease the oscillation frequency of the reference signal if the reception interval of the received control signal is shorter than the predetermined time. The wireless communication system according to claim 5, wherein the wireless communication system is controlled to do so. A method for adjusting a communication frequency of a wireless communication system including a control station and at least one subordinate station capable of communicating with the control station,
The control station receives a TDMA radio signal transmitted from another radio communication apparatus, and adjusts a communication frequency for TDMA radio communication with the dependent station based on the received radio signal. A method for adjusting a communication frequency of a communication system. A method for adjusting a communication frequency of a wireless communication system including a first control station, a second control station, and the first control station or a dependent station capable of communicating with the second control station,
The second control station receives a TDMA radio signal transmitted from the first control station, and based on the received radio signal, sets the frequency accuracy of the radio signal transmitted by the second control station to the first control station. 8. The method of adjusting a communication frequency of a wireless communication system according to claim 7, wherein the communication frequency is adjusted so as to match the frequency accuracy of a wireless signal transmitted by the wireless communication system. The first control station generates a radio signal of the control signal based on the first reference signal and determines a transmission interval, and the second control station performs radio communication based on the second reference signal. Generating a high-frequency signal for the control signal, measuring a reception interval of the control signal transmitted from the first control station, and adjusting the second reference signal so that the reception interval becomes a predetermined time interval 請 Motomeko 8 adjusting method of a communication frequency of the wireless communication system according you adjust the communication frequency by. A method for adjusting a communication frequency of a wireless communication system including a first control station, a second control station, and the first control station or a dependent station capable of communicating with the second control station,
The second control station receives a radio signal transmitted from the first control station, adjusts a communication frequency based on the received radio signal, and the dependent station has the first control station When both the radio signal to be transmitted and the radio signal to be transmitted by the second control station are received, the communication frequency is adjusted based on the radio signal to be transmitted by the first control station. When only the radio signal transmitted by either one of the first control station and the second control station is received, the first control station or the second control station that is receiving is received. The method for adjusting a communication frequency of a radio communication system according to claim 8 or 9, wherein the communication frequency is adjusted based on a radio signal transmitted by the control station. The dependent station generates a high-frequency signal for wireless communication based on one reference signal and is transmitted from the reception interval of the wireless signal transmitted from the first control station or from the second control station. The method of adjusting a communication frequency of a wireless communication system according to claim 10 , wherein a communication frequency is adjusted by measuring a reception interval of a wireless signal and adjusting the reference signal based on each reception interval. A radio communication system communication frequency comprising a first control station, a first dependent station capable of communicating with the first control station, a second control station, and a second dependent station capable of communicating with the second control station. Adjustment method,
The second control station receives a radio signal transmitted by the first control station, adjusts a communication frequency based on the received radio signal, and the first subordinate station The control station receives a radio signal transmitted from the control station, adjusts a communication frequency based on the received radio signal, and the second dependent station receives and receives a radio signal transmitted from the second control station. A method for adjusting a communication frequency of a wireless communication system that adjusts a communication frequency based on a wireless signal. At least one of the first dependent station and the second dependent station receives a control signal transmitted from the control station to which the first dependent station belongs, and is transmitted from the control station to which the control station belongs by the time measuring means. 13. The method of adjusting a communication frequency of a wireless communication system according to claim 12, wherein a communication frequency is adjusted by measuring a reception interval of a radio signal and adjusting the reference signal based on the reception interval.

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