KR100308176B1 - System for processing rf composite signal of radio receiver and method for controlling the same - Google Patents

Abstract

There are a plurality of ultra-high frequency RF signal processing systems and a control method of installing a transmitter for wirelessly transmitting an ultra-high frequency RF signal to a multi-channel CCD camera and receiving and processing the high frequency signal by a transmitter adapted to receive and process the digital signal. Select the RF complex signal and convert it down to an intermediate frequency to convert it into a fixed intermediate frequency. The fixed intermediate frequency is processed into a video signal and an audio signal, and the baseband synchronization signal of the video signal is detected. The display device may be selectively displayed or divided on the display device and may be simultaneously displayed on multiple display devices as necessary.

Description

Ultra High Frequency RF Combined Signal Processing System for Radio Receiver and Its Control Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RF signal processor of a wireless receiver, and more particularly, to a system for controlling an RF signal processing system and a control method thereof of a wireless receiver adapted to be applied to a closed circuit television (CCTV) that can sequentially and simultaneously process an RF signal. will be.

CCTV is basically composed of three kinds of image pickup device (CCD camera), transmission device and display device, and recently, it has been used in various ways by adding a recording device to it.

This invention does not relate to an imaging device and a display device but to a transmission device. In particular, this transmission device receives a radio RF signal from an image pickup device, and is designed to facilitate digital processing of the signal, thereby enabling MPEG processing.

To this end, the present invention uses a carrier wave containing a video and audio signal having a frequency of 2,4 GHz, an intermediate frequency of 479,5 MHz, and an intermediate frequency of 479,5 MHz as an ultrahigh-frequency RF complex signal.

The RF composite video signal of these carriers is different from the VHF band 54-88MHz or 174-216MHz or UHF band 470-890MHz, which is used in general television transmission or cable television system, and their intermediate frequency video carrier 45,75MHz and audio. It is completely different from the carriers 41,25 MHz and the color carriers 42,17 MHz.

On the other hand, MPEG2 and above signals are related to moving picture compression technology. When digitizing and storing or transmitting analog data, the amount of data is enormous and requires a large bandwidth, and the transmission rate must be 5 Mbit / sec or more. This digital data signal is a bit stream coded audio and video data, and other preservation data, which should be packetized, multiplexed, and used as a transport stream for storage or transmission in another medium. In this case, although the transport stream corrects an error in transmission through a network or a satellite according to an error correction technique, a significant error occurs according to an environment.

For this reason, so far, MPEG technology has been used in broadcasting environments, ATM networks, computer networks, or information highway networks using optical fibers for the purpose of delivering moving images, audio, and data.

The MPEG technology has not been applied to CCTV so far, and in CCTV, the data transmission device mainly uses a cable, and no attempt has been made to transmit data wirelessly. In addition, it was impossible to process complex signals using existing FM RF frequencies in CCTV systems to which MPEG technology is applied.

Therefore, the present invention mainly deals with providing an RF composite signal processing system and a control method thereof, in which an RF composite signal serving as an ultra-high frequency carrier is applied to MPEG technology so that a display device such as a personal computer outputs an audio signal of a moving image. do.

Another object of the present invention is to provide an ultra-high frequency RF complex signal processing system and a control method thereof which sequentially scans an ultra-high frequency RF signal from a plurality of CCD cameras according to channel selection to be displayed on a display device such as CCTV.

It is still another object of the present invention to receive a high frequency RF signal from a plurality of CCD cameras and to apply it to MPEG technology, so that a moving picture and audio signal can be stored in a storage medium installed in a personal computer and alerted as necessary. It is to provide a system and a control method thereof.

1 is a block diagram schematically showing another ultra-high frequency RF signal processing system according to the present invention.

2 is a circuit diagram showing in detail the receiver, mixer, local oscillator, matched filter, amplifier and demodulator of the ultra-high frequency RF complex signal processing system according to the present invention.

3 is a circuit diagram showing in detail an audio processor, an image signal processor, and a demultiplexer of an ultra-high frequency RF complex signal processing system according to the present invention.

4 is a flowchart showing a method for processing an ultra-high frequency RF complex signal according to the present invention.

<Description of the symbols for the main parts of the drawings>

1 antenna 2 receiver

3: mixing section 4: local oscillation section

5: matching filter unit 6: amplifying unit

7 demodulation unit 8 voice signal processing unit

9: Image signal processing unit 10: Control unit

11: demultiplexer

The present invention provides a 2,4 GHz ultra-high frequency RF signal transmitter in an image pickup device such as a CCD camera having one or more channels, and the receiver receiving the RF compound signal from the image pickup device has a high frequency RF compound signal processing in addition to the MPEG board. A system comprising: a receiver for receiving and amplifying an ultrahigh frequency RF signal in a 2,4 GHz band; A local oscillation unit for generating a predetermined 1,9 GHz band frequency signal in accordance with a signal for selectively controlling the composite signal processing described below; A mixer for self-filtering the amplified signal from the receiver and receiving a 1,9 GHz band frequency signal from the local oscillator to downconvert one or more signals in the 2,4 GHz band to a fixed intermediate frequency of 479,5 MHz; A matching filter unit for matching the intermediate frequency to a high precision intermediate frequency; An amplifier for amplifying the matching intermediate frequency signal in multiple stages; A demodulator for generating an intermediate frequency (IF) carrier demodulated signal from which the signal is converted into an MPEG processing voltage and phase locked; A voice signal processor for receiving a signal from the demodulator and applying the signal to the modulator via the housewife voice band signal 6MHz and the 6,5MHz band filter, respectively, to generate voice signals in the left and right channels; An image signal processor for filtering and amplifying the signal from the demodulator through a notch filter; A demultiplexer for selecting and outputting any one or all of the signals of the image signal processor under the control of the controller; The controller is configured to detect the image synchronization signal from the notch filter unit to determine the current channel output and to display the output of the corresponding channel or display the output of all channels for a predetermined time according to the channel selection input of the image switch.

In order to process such an ultra-high frequency RF complex signal, the present invention includes the steps of detecting a baseband synchronization signal for a channel; Analyzing the sync signal to determine whether it is the currently selected channel, or analyzing the signal if it is not the selected channel sync signal to generate a warning signal if there is a problem in the transmission path; Outputting predetermined phase locked data to the local oscillator to display data of a next display channel among the plurality of channels; Analyzing a synchronization signal of a baseband corresponding to this channel; Displaying the output of the channel through the image switch of the channel for a predetermined time; By repeating these steps, the ultrasonic RF composite signal processing method for causing the display device to display received data at least four times is performed.

In addition, the control unit is provided with an RF composite signal processing unit corresponding to each channel as an input of the demultiplexer, and when a display device is installed at an output corresponding to the multiplexer, the control unit can simultaneously process images of a plurality of channels.

Therefore, the present invention can be applied to MPEG technology to receive an ultra-high frequency RF complex signal capable of processing a large amount of data from a plurality of channels so that they can be displayed sequentially or simultaneously over time.

This invention is described in detail based on the accompanying drawings as follows.

An ultrasonic RF composite signal receiver is connected to a display device having a storage device such as a personal computer, and includes an MPEG board (not shown) for processing a moving picture and an audio signal, and generates a video and audio signal matched to the MPEG board. An ultrasonic RF composite signal processing system 100 is provided.

This system 100 receives by the antenna 1 an ultra-high frequency RF complex signal from an imaging device (not shown), such as one or more CCD cameras. The receiver 2 connected to the antenna 1 tunes and amplifies a composite signal of 2,4 GHz over multiple stages. This RF carrier is amplified and then applied to the mixing section 3, which functions as an intermediate frequency (IF) filter composed of a downconverter described later to generate an intermediate frequency.

That is, the mixing section 3 receives a plurality of RF carriers in the 2,4 GHz band from one or more channels, and at the same time receives and converts the oscillation signal of the 1.9 GHz band from the local oscillating section 4, thereby a fixed intermediate frequency. A carrier signal of 479.5 MHz is output. The local oscillator 4 includes a synthesizer having an intermediate frequency tuning function and generates a tuning frequency of a predetermined 1.3 GHz band according to a control input from the controller 10 and applies it to the mixing section 3.

The output from the mixing section 3 is applied to the matching filter section 5 and again matched so that the intermediate medium frequency has high accuracy.

The matched intermediate frequency signal is applied to the amplifier 6, and the amplifier 6 amplifies and filters the matched intermediate frequency signal first, and then amplifies and outputs it in multiple stages.

The demodulator 7 converts the signal from the amplifier 6 into an MPEG processing voltage and outputs an IF carrier demodulated signal which is phase locked.

This demodulated signal is simultaneously applied to the audio signal processing section 8 and the video signal processing section 9. The audio signal processor 8 includes a first sub band pass filter 12 and a first demodulator 13 to filter and demodulate a 6 MHz band audio signal and output the audio L or left channel signal. A subband pass filter 14 and a second demodulator 15 are provided to filter, demodulate, and output the audio signal of the 6.5 MHz band as an audio R or right channel signal.

The video signal processor 9 is composed of a notch filter unit 16 and an amplifier 17 to process, amplify, and output a carrier signal of intermediate frequency from the demodulator 7 into an image composite signal.

At this time, the video composite signal is applied to the controller of the controller 10 to analyze which camera the current video signal is.

The demultiplexer 11 selects an input video signal and outputs it to a PC monitor or the like via a predetermined MPEG board to display an image.

The controller 10 generates a signal for controlling the local oscillator to select a predetermined RF frequency according to an external image switch input so that the mixing unit 3 determines the received RF signal.

In addition, the control unit 10 detects the composite image signal, determines whether the baseband synchronization signal of the current channel is present, and displays a predetermined image on the PC monitor according to the selected channel.

Ultra-high frequency RF complex signal processing system composed of such a block is more specifically configured as follows.

The receiver 2 includes a multistage tuning unit and an amplifying unit 24. The first tuning unit 21, the second tuning unit 22 and the third tuning unit 23, which are multistage tuning units, have a plurality of resistors. And an oscillation tuning circuit of condensers to tune the composite signal input through the antenna 1. Here, the constants and configurations of these resistors and capacitors are known in the art, and thus detailed descriptions are omitted. Thereafter, the tuned signal is amplified and output by the amplifier 24 composed of the operational amplifier OP1 and the transistor TR1.

The mixing unit 3 includes a down converter 25 and an RF filter F1 is connected to receive the RF composite signal from the receiving unit. The down converter 25, as an IF filter, receives a predetermined oscillation signal of the 1.9 GHz band from the local oscillator 4, downconverts the signal of the 2.4 GHz band from the receiver 1 as a local oscillation signal, and fixes a fixed intermediate frequency. Output (479.5MHz).

The local oscillator 4 selects and generates a predetermined oscillation frequency in the 1.9 GHz band according to the control of the controller 10, and a control signal from the terminal COM1 is applied to the same comparator 26 via the transistor TR2. do. The synthesizer 26 determines the local oscillation frequency according to the control signal, generates a tuning frequency in the 1.9 GHz band, and applies it to the mixing section 3.

This synthesizer 26 has a model name TSA50557 and is provided with an oscillator 0SC1 to generate a tuning signal itself.

The matched filter part 5 includes a filter F2, and a precision fixed match in which a capacitor C3 is connected in parallel to a capacitor C2 and a coil L2 at a front end thereof and a capacitor C4 at a rear end thereof. The intermediate frequency carrier, which is composed of a filter and is adjusted with high precision, is applied to the amplifier 6.

The amplifier 6 is composed of a multi-stage amplifier, which is first amplified by the transistor TR3 and second amplified by the transistor TR4, in which an oscillator 0SC2 is connected to its collector and has an intermediate frequency. Be tuned to the carrier.

The carrier is then amplified and output by the operational amplifier OP2. The transistors TR5 and TR6, which have not been described, are composed of an amplifier and maintain a stable voltage state with respect to the input intermediate frequency carrier and have the same voltage as the demodulator 7.

The demodulator 7 has a wideband PLL FM demodulator 27 whose model number is SL146ISA. The demodulator 27 demodulates the input amplified intermediate frequency carrier to the image composite signal. In addition, the demodulator 27 is composed of a voltage controlled oscillator VCO composed of diodes D1 and D2 to operate stably at temperature and power. The voltage controlled oscillator VCO may be designed to change the voltages of the transistors TR5 and TR6 of the amplifier 6 so that the demodulation output has an advantageous voltage value for MPEG processing. The demodulated signal thus processed is simultaneously applied to the audio signal processor 8 and the video signal processor 9 via the common terminal COM2 and the input terminal COM3.

The audio signal processor 8 is composed of an audio left channel and a right channel, the left channel is composed of a first sub band pass filter 12 and a first demodulator 13, and the right channel is a second sub band pass filter ( 14 and the second demodulation unit 14.

The first subband pass filter 12 includes a filter F4, a transistor TR7, and an oscillator configured as a peripheral circuit thereof. The demodulator of the first demodulator 13 filters the demodulated signal with a voice signal carrier in a 6 MHz band. Is applied to (28).

The demodulator 28 is an audio FM demodulator and amplified by transistors TR8 and TR9 to output audio signals of the left channel. Here, the transistor TR10 keeps the operating voltage of the demodulator 28 stable.

Similarly, in the voice processing of the right channel, a demodulation signal is first applied to the second sub band pass filter 14. The second subband pass filter 14 filters the voice carrier in the 6.5 MHz band including the filter F5, the transistor TR11, and the peripheral circuit. This signal is applied to the second demodulator 29 of the second demodulator 15. The demodulator 29 modulates the voice signal, amplifies it through the transistors TR12 and TR13 and outputs the voice signal of the right channel. Here, the transistor TR14 keeps the operating voltage of the demodulator 29 stable.

The image signal processor 9 receives a complex video signal of a carrier having an intermediate frequency from the demodulator 7, and the notch filter unit 16 amplifies the RF demodulated signal by the transistors TR15 and TR16. . The notch filter section 16 further comprises a low frequency filter stage consisting of resistors R10, R11, R12, capacitors C6, and C7 connected to the collectors of transistors TR17 and TR18. The coils L3, L4, and the capacitor C8, and the capacitors C9 and C10 connected in parallel with each other, are composed of an LRC filter composed of a resistor R13. Therefore, the notch filter unit 16 removes the low frequency of the composite video signal from the RF demodulated signal and is applied to the amplifier 17.

In the amplifier 17, the composite video signal is amplified via the transistors TR19 and TR20, and amplified by the transistor TR21, and then applied to the demultiplexer 11.

On the other hand, the output terminal of the transistor TR20 is connected to the controller 30 of the controller 10 to detect the synchronization signal. The controller 30 is a conventional microcontroller and programmatically controls this system as described later. The controller 30 detects and analyzes the synchronization signal, determines whether the current input signal is an image display signal, and outputs a control signal to the demultiplexer 11. The demultiplexer 11 applies the image-processed image display signal to the MPEG board according to the control signal to be displayed on the PC monitor. To this end, the controller 10 includes an external oscillator for timing the controller 30 to input the image input switches SW1 to SW5 as inputs and to display the partitioned division of the multiple channels. The external oscillator comprises a peripheral circuit such that the oscillator 31 having the variable resistor VR1 which can be externally adjusted so that the oscillation time is arbitrarily set has a predetermined time constant value. The time constant is determined in the range of 10 seconds to 60 seconds.

The power supply unit 18 is configured to supply system power, and is configured using predetermined constant voltage (regulator) ICs 32 and 33. The ultra-high frequency RF composite signal processing system configured as described above is controlled by the controller 30 of the controller 10 as follows.

As shown in FIG. 4, when initialized in step 101, it is determined in step 102 whether a predetermined time delay is applied. This delay time is very important and prevents the image signal demultiplexed by this RF system from being incorrectly displayed as an image by the MPEG board as it is. If the predetermined delay time has elapsed in step 10, the flow advances to step 103 to determine the input of the image switch. At this time, if the divisional display of the image switch is not displayed, the display device division setting is made in step 104. In step 105, the channel data setting is confirmed, and the process proceeds to step 106 to confirm whether or not the video signal of the selected channel is applied, which detects the output of the notch filter unit 16 as described above. As the analysis is done. At this time, if it is not the selected synchronization signal, the process returns to step 107 to determine whether the selected channel again. If not, it generates a warning signal in step 108 and confirms that the next channel is selected.

On the other hand, if the selected synchronizing signal is confirmed in step 106, the process proceeds to step 109 to display or segment display the image signal of the selected channel.

Thereafter, in step 110, the next channel is set, and the process proceeds to step 111 to determine whether the selected baseband synchronization signal is present. If it is not the selected channel it is determined again in step 112. If it is the selected channel, the channel data setting is checked and if not, the warning signal is generated in step 113.

If it is the baseband synchronization signal in step 111, the process proceeds to step 114 to display channel data or partition display. In step 115, the same operation is repeated four or more times, and successively confirms the initial or intermediate channel data setting using the same display method unless there is a change to the division display of the image switch.

The present invention constructed as described above can be used in next-generation digital monitors, and in order to be applied thereto, audio and video signals are digitally processed in MPEG boards by processing ultra-high frequency RF carrier analog composite signals wirelessly received from multiple channels and processing digital images. To be possible. In addition, the RF composite signal processing system can display a plurality of channels on a single monitor or display them sequentially, as well as display all channels simultaneously corresponding to a plurality of channels.

Claims (5)

A transmitter applied to a 2.4 GHz ultra-high frequency RF complex signal transmitter installed on a CCD camera having a plurality of channels and receiving the same and processing the same into a digital signal, the transmitter comprising: a receiving unit for receiving and tuning and amplifying ultra-high frequency RF signals; A local oscillator for generating an oscillation signal having a predetermined frequency in the 1.9 GHz band according to the control signal from the controller; A mixing section for down-converting the predetermined frequency reception signal from the reception section to a fixed intermediate frequency of the signal from the local oscillator; A matching filter unit for matching the intermediate frequency to a high precision intermediate frequency; An amplifying unit which multi-stages the matched intermediate frequency signal; A demodulator for generating an intermediate frequency carrier demodulated signal whose phase is fixed by changing the signal from the amplifier to an MPEG processing voltage; A voice signal processor which receives the signal from the demodulator, filters the housewife audio band signal, and applies the demodulator to the demodulator, thereby generating left and right channel audio signals; An image signal processing unit for filtering and amplifying low frequency signals by passing a signal from the demodulator through a notch filter unit; A demultiplexer for selecting and outputting any one or all of the signals of the image signal processor under the control of the controller; RF signal of a predetermined channel is selected in the mixing section by selecting the oscillation signal of the local oscillator, and generates an intermediate frequency carrier, detects the baseband synchronization signal of the adjustment channel, and configures the control signal to display the selected channel signal. Compound Signal Processing System. 2. The RF signal processing system according to claim 1, wherein a matched filter unit is provided between the mixing unit and the amplifying unit. The ultra-high frequency RF complex signal processing system according to claim 1, wherein the control unit causes one or more channel images to be displayed simultaneously according to the input of the image switch. The ultra-high frequency RF complex signal processing system according to claim 1, wherein the control unit has a predetermined delay time to sequentially display images of the selected channel. CLAIMS 1. A control method of an ultra-high frequency RF composite signal processing system, comprising: detecting a synchronization signal of a baseband for a channel; Controlling a local oscillator to display data of a next display channel among a plurality of channels to output a predetermined frequency; Analyzing a synchronization signal of a baseband corresponding to this channel; Displaying the output of the channel through the image switch of the channel for a predetermined time; And repeating these steps to display received data on the display device at least four times.