JPH0896284A - Wireless security system - Google Patents

Abstract

PURPOSE: To suppress the power consumption of a transmitter and to prevent output information from being failed due to wave interruption from the external by transmitting signals with one transmission frequency band at the time of periodical transmission for monitoring a transmission state, and at the time of transmitting output information, using plural transmission frequency bands. CONSTITUTION: A communication control part 10 executes the management of periodical transmission for transmitting a radio signal at a fixed period by the use of an internal timer and the management of information transmission for transmitting output information corresponding to an output from a security sensor 16. At the time of periodical transmission, an identification(ID) code signal from the transmitter is transmitted to a VCO 12 through a modulation circuit 3 and a signal for determining transmission frequency f1 corresponding to the periodical transmission is applied to a PLL synthesizer 13. At the time of transmitting output information, the output information and an ID code are prepared, these signals are transmitted to the VCO 12 and signals for determining two transmission frequency bands f1 , f2 corresponding to the information transmission are alternatively applied to the synthesizer 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to wireless security systems.

[0002]

2. Description of the Related Art FIG. 8 shows the overall configuration of a wireless security system. This system comprises a receiver 2 which constitutes a controller, and a transmitter 1 which is integrated with or connected to various security sensors. When the sensor provided integrally or connected to the device 1 detects an abnormality and issues an alarm, the alarm information is transmitted by a radio wave radio signal together with an identification code (address) for identifying each transmitter 1,
The receiver 2 receives the radio wave radio signal, demodulates the alarm information and the identification code, and issues an alarm based on the contents of the transmitter 1 and the alarm information that have been notified, or sends information to the central monitoring center through the telephone line. It is designed to transmit.

In this system, there is no need for wiring between the receiver 2 and the transmitter 1, and there is an advantage that the transmitter 1 can be freely installed within a range where radio wave signals can reach the receiver 2. By the way, since there is a problem in a security system when a false alarm occurs, the transmitter 1 periodically transmits a radio wave radio signal carrying information such as an identification code, and the receiver 2 receives the radio wave radio signal by the regular transmission. By doing so, it is possible to monitor radio wave interference and the like. With such regular transmission, it is possible to find a trouble such as a radio radio signal that cannot be received for a long period of time, and prevent serious misinformation.

By the way, in the above wireless security system, if the transmission frequency of the radio wave radio signal transmitted from the transmitter 1 is only one frequency, the alarm information cannot be received by the receiver 2 when there is radio interference from the outside. was there. Therefore, radio wave radio signals are transmitted using a plurality of transmission frequencies to cope with radio wave interference.

[0005]

However, when a plurality of transmission frequencies are used as described above, in the above-described regular transmission, transmission is performed at each transmission frequency, so that the power consumption in the transmitter 1 is reduced accordingly. growing. Usually, in a wireless security system, a battery power source is used as the power source of the transmitter 1. Therefore, if the power consumption is large, there is a problem that the battery must be frequently replaced.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress power consumption of a transmitter and also to prevent electromagnetic interference from the outside. It is to provide a wireless security system that can prevent the loss of information. In addition to the object of the invention described in claim 1, an object of the invention described in claims 2 to 5 is to provide a wireless security system in which the probability of false alarm is further reduced.

[0007]

According to a first aspect of the present invention, a transmitter for transmitting notification information of various security sensors by a radio wave radio signal, and a radio wave radio signal transmitted by the transmitter are issued and transmitted. In a wireless security system consisting of a receiver that demodulates the broadcast information, a radio frequency signal for monitoring the transmission status is periodically transmitted. It is characterized in that the transmitter is provided with means for sequentially transmitting the alarm information at each transmission frequency using a plurality of transmission frequencies.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of receiving antennas, antenna switching means for sequentially and cyclically connecting the receiving antennas to be used, and receiving corresponding to each transmission frequency of the transmitter. The receiver is provided with receiving frequency switching means for sequentially and cyclically switching and setting the frequency. The invention of claim 3 is characterized in that, in the invention of claim 2, switching setting of each reception frequency is performed during a connection period of each reception antenna.

According to a fourth aspect of the invention, in the second aspect of the invention, each receiving antenna is switched and connected during the setting period of each receiving frequency. According to a fifth aspect of the invention, in the second aspect of the invention, the receiver mixes the received high-frequency signal and the oscillation signal from the local oscillation circuit with the frequency conversion circuit to convert the high-frequency signal into an intermediate frequency. A local oscillating unit is configured by a plurality of crystal oscillators that individually generate an oscillation signal of a frequency corresponding to each reception frequency and a switching unit that switches the crystal oscillators and connects the oscillation signal to the frequency conversion circuit. The feature is that the crystal oscillators are sequentially switched.

[0010]

According to the first aspect of the present invention, a radio frequency signal for monitoring the transmission state is transmitted at one transmission frequency during regular transmission, and a plurality of transmission frequencies are transmitted during transmission of alarm information. Since the transmitter is equipped with means for transmitting alert information at each transmission frequency in sequence, it is possible to suppress power consumption during regular transmission that does not pose a problem even if there is a temporary loss of information. It is very effective when using a power source, and since the alert information is transmitted using multiple transmission frequencies, even if there is interference from the outside, the alert information of the receiver can be lost. Can be prevented.

According to a second aspect of the present invention, in the first aspect of the invention, a plurality of receiving antennas, an antenna switching means for sequentially and cyclically connecting the receiving antennas to be used, and corresponding to each transmitting frequency of the transmitter. Since the receiver is provided with the receiving frequency switching means for sequentially and cyclically setting the receiving frequencies described above, it is possible to reduce the false alarm probability by combining a plurality of frequency switching and the diversity receiving system.

According to the invention of claim 3, in the invention of claim 2, since switching setting of each receiving frequency is performed in the connection period of each receiving antenna, after selection is made compared with the time required for switching connection of the receiving antenna. It is possible to cope with the selection of the reception frequency which takes time to stabilize from the. According to the invention of claim 4, in the invention of claim 2, since the switching connection of each receiving antenna is performed in the setting period of each receiving frequency, the receiving antenna can be switched and connected at a high speed. Compared to the case of the invention, the number of reception conditions that can be set within the same period by the combination of the reception antenna and the reception frequency can be increased, so that efficient transmission can be performed and the false alarm probability can be further reduced. .

According to the invention of claim 5, in the invention of claim 2, the receiver mixes the received high-frequency signal and the oscillation signal from the local oscillating section by the frequency conversion circuit to convert them into an intermediate frequency. A plurality of crystal oscillators that individually generate oscillation signals of frequencies corresponding to the respective reception frequencies,
A local oscillator is configured by means of switching between these crystal oscillators and connecting an oscillation signal to the frequency conversion circuit, and since the crystal oscillators are sequentially switched and the reception frequency is switched and set,
The reception frequency and the reception antenna can be switched at a higher speed than in the inventions of claims 3 and 4, so that the false alarm probability can be further reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows a circuit block of a transmitter 1 of this embodiment. This transmitter 1 includes a communication control unit 10, a modulation circuit 11, a VCO 12, and a PLL synthesizer 13.
The RF transmission circuit 14, the transmission antenna 15, the security sensor 16 connected to the communication control unit 10, and the battery power source V.

The communication control unit 10 is for controlling the transmission of the radio wave radio signal of the transmitter 1. The communication control unit 10 controls the periodical transmission of transmitting the radio wave radio signal at a constant cycle by the internal timer, and issues the alarm for the security sensor 16. The notification transmission is performed by transmitting the notification information according to the radio wave signal, and at the time of regular transmission, for example, an identification code (address) of the transmitter 1 is created and the identification code signal is transmitted through the modulation circuit 3 to the VCO 12
And a signal for determining the transmission frequency f ₁ corresponding to the periodic transmission to the PLL synthesizer 13, and at the time of the alert transmission, the alert information and the identification code corresponding to the alert of the security sensor 16 are sent. And send these signals to the voltage signal input terminal v of the VCO 12 through the modulation circuit 3 and transmit frequencies corresponding to the alert transmission to the PLL synthesizer 13 ( _two f ₁ and f _{2 in} the embodiment). Alternate signals to determine.

The PLL synthesizer 13 has a communication controller 11
A voltage signal for generating a desired frequency from the VCO 12 controlled by a signal output from the VCO 12 is output to the voltage signal input terminal v of the VCO 12. VCO1
2 generates a frequency signal determined by the voltage signal from the PLL synthesizer 13, and the frequency signal is modulated by the signal from the modulation circuit 3.

The RF transmission circuit 14 power-amplifies the frequency signal output from the VCO 12 and transmits it as a radio wave radio signal from the transmission antenna 15. Under the control of the communication control unit 11, the transmitter ₁ transmits a radio wave radio signal at a transmission frequency of f ₁ as shown in FIG. On the other hand, at the time of report transmission, as shown in FIG. 2B, the radio frequency radio signal having the transmission frequency f ₁ and the radio frequency radio signal having the transmission frequency f ₂ are alternately transmitted to deal with the radio wave interference. In this embodiment, the radio frequency signal is transmitted by switching the transmission frequency every 10 seconds until it is reset.

Here, the radio wave radio signal at the time of transmitting the alarm information is, as shown in FIG. 2B, a preamble part X ₁ and a data part X.
Composed of ₂ and. Receiver 2 corresponding to the transmitter 1
As shown in FIG. 3, the two receiving antennas 20a, 20a
b, a changeover switch unit 21 for switching and connecting the receiving antennas 20a and 20b, and an RF receiving circuit 22 for filtering and amplifying a received signal.
, A local oscillator 23, a frequency converter 24 that mixes an oscillation signal from the local oscillator 23 and an output signal of the RF receiver circuit 22 and converts it into an intermediate frequency, and an intermediate frequency output from the frequency converter 24. IF unit 25 for amplifying the signal, a demodulation circuit 26 for demodulating alarm information and identification code data from the signal output from the IF unit 25, switching control of the antenna changeover switch unit 21 and output frequency of the local oscillator unit 23. And a communication control unit 27 that manages the entire receiver 2 such as alarm switching control based on demodulated data and notification processing to a central monitoring center. In addition, the reception frequency is switched by switching the output frequency of the local oscillator 23.

The local oscillator 23 includes a VCO 23a and a PLL.
The synthesizer 23b is configured to control the PLL synthesizer 23b by a signal output from the communication control unit 27 so that an oscillation signal of a desired frequency is output from the output end f of the VCO 23a. Thus, in the receiver 2 of the present embodiment, the communication control unit 27 controls the PLL synthesizer 23b to switch the frequency of the oscillation signal output from the VCO 23a at a constant cycle to obtain the reception frequency of f ₁ .
The reception frequency of f ₂ is alternately set in FIG. 4A, and the reception antennas 20a and 20b connected by controlling the antenna changeover switch unit 21 in the setting period of the reception frequencies f ₁ and f ₂ are shown in FIG. Alternately switch as shown in (b).

That is, the receiving antennas 20a and 20b can be switched instantaneously, whereas the PLL synthesizer 20b can be switched.
Since it takes a time (T) of about several tens of ms to select and set the reception frequency by the method, the receiver 2 of the present embodiment minimizes the number of times the reception frequency is switched and set for efficient transmission. Here, the period of the preamble part X ₁ of the radio wave signal of the transmitter 1 is set to a length such that the set period of the reception frequency f _{1 and} the set period of the reception frequency f ₂ are included as shown in FIG. and, thus in the case of receiving antennas 20a at the receiving frequency f _1, and if the receiving antenna is 20b at the receiving frequency f _1, the receiving frequency f
_Since four types of reception conditions are set in the preamble X ₁ when the reception antenna is 20a in ₂ and the reception antenna is 20b in the reception frequency f ₂ , bit synchronization can be achieved under any of the reception conditions. In this case, the communication control unit 27 receives the data by setting the frame synchronization in the setting.

Although FIG. 5 shows that the reception frequency is f ₂ and the bit synchronization is achieved when the reception antenna 20b is used, the bit synchronization is performed under the conditions up to then (for example, the reception frequency is f ₁ and the reception antenna is 20b). If the above condition is satisfied, the data is received under the reception condition without further selection setting of the reception frequency and switching connection of the reception antenna. In the receiver 2, the receiving antennas are switched by giving priority to the selective setting of the receiving frequency. However, as shown in FIGS. 6A and 6B, the receiving antennas 20a and 20b are switched at a constant cycle. And each of the receiving antennas 20a, 20
During the connection period of b, the reception frequency may be alternately switched between f ₁ and f ₂ . In this case, the number of reception conditions that can be set in the same period is as small as 8 in the above case.

The PLL synthesizer 22b and the VCO 22
Instead of the local oscillator 23 by a, for example, each reception frequency
Number f₁, F₂The crystal oscillator and the oscillator
A crystal oscillator connected to an oscillator using a local oscillator 23
Is oscillated by a control signal from the communication control unit 27
Set the frequency of the oscillation signal output from the unit 23 and receive
The frequency may be switched. (Embodiment 2) In the receiver 2 of Embodiment 1, the local oscillator 2 is used.
3 using VCO 23a and PLL synthesizer 23b
Therefore, it takes time to set the reception frequency.
As shown, each reception frequency (for example, three frequencies f₁, F
₂, F₃) Crystal oscillator OSC corresponding to each₁~ OS
C₃The local oscillator 23 is composed of these crystal oscillators OS
C₁~ OSC₃A of the output section of₁~ A₃And B₁~ B₃Each of
By controlling the electric potential with the communication control unit 27, the
Wave number f₁~ F₃Crystal oscillator OSC₁~ OSC ₃Oscillation
Select whether to output the signal to the frequency conversion circuit 24
I have to.

That is, the setting of switching the receiving frequency can be made almost instantaneously similarly to the switching of the receiving antennas 20a and 20b, and the number of receiving conditions that can be set within the same period is increased to further reduce the false alarm probability. I am trying to do that. The operation of the receiver 2 of the first embodiment is the same as that of the receiver 2 of the first embodiment except the operations of the local oscillator 23 and the communication control unit 27 for setting the frequency switching of the local oscillator 23. The illustration and description of are omitted.

[0024]

According to the first aspect of the present invention, a radio frequency signal for monitoring the transmission state is transmitted at one transmission frequency during periodic transmission, and a plurality of transmission frequencies are transmitted during notification information transmission. Since the transmitter is equipped with means for transmitting alert information at each transmission frequency in sequence, it is possible to suppress power consumption during regular transmission that does not pose a problem even if there is a temporary loss of information. It is very effective when using a power source, and since the alert information is transmitted using multiple transmission frequencies, even if there is interference from the outside, the alert information of the receiver can be lost. The effect is that it can be prevented.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of receiving antennas, an antenna switching means for sequentially and cyclically connecting and connecting the receiving antennas to be used, and receiving corresponding to each transmission frequency of the transmitter. Since the receiver is provided with the reception frequency switching means for sequentially and cyclically setting the frequency, there is an effect that the false alarm probability can be reduced by combining a plurality of frequencies and the diversity reception system.

According to a third aspect of the present invention, in the second aspect of the present invention, since switching setting of each reception frequency is performed in a connection period of each reception antenna, it is stable after selection as compared with a time required for switching connection of the reception antenna. There is an effect that it is possible to cope with the selection of the reception frequency, which takes time to perform. According to the invention of claim 4, in the invention of claim 2,
Since the receiving antennas are switched and connected during the setting period of each receiving frequency, the receiving antennas can be switched and connected at a high speed, and the receiving antenna and the receiving antenna that can be set within the same period as compared with the case of the invention of claim 3. It is possible to increase the number of reception conditions depending on the combination with the frequency, and therefore, it is possible to perform efficient transmission and further reduce the false alarm probability.

According to a fifth aspect of the present invention, in the second aspect of the present invention, the receiver mixes the received high frequency signal and the oscillation signal from the local oscillating section with a frequency conversion circuit to convert them into an intermediate frequency. Therefore, a local oscillating unit is configured by a plurality of crystal oscillators that individually generate an oscillation signal of a frequency corresponding to each reception frequency and a means for switching the crystal oscillators and connecting the oscillation signal to the frequency conversion circuit. Since the oscillator is sequentially switched and the reception frequency is switched and set, the reception frequency and the reception antenna can be switched faster than in the inventions according to claims 3 and 4, so that the false alarm probability can be further reduced. There is an effect.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a transmitter according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining regular transmission and notification transmission of the transmitter of the above.

FIG. 3 is a circuit block diagram of the above receiver.

FIG. 4 is a timing chart for explaining switching connection of receiving antennas and selective setting of receiving frequency of the receiver.

FIG. 5 is a timing chart for explaining signal reception of the above receiver.

FIG. 6 is a timing chart for explaining another example of the switching connection of the receiving antennas and the selective setting of the receiving frequency in the above.

FIG. 7 is a circuit diagram of a local oscillating unit of a receiver according to a second exemplary embodiment of the present invention.

FIG. 8 is a system configuration diagram of a wireless security system.

[Explanation of symbols]

 1 Transmitter 10 Communication Control Unit 11 Modulation Circuit 12 VCO 13 PLL Synthesizer 14 RF Transmitter Circuit 15 Receiving Antenna 16 Security Sensor V Battery Power Supply

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiro Kikuchi 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Takeshi Kuno, 1048, Kadoma, Kadoma City, Osaka Matsushita Electric Works Co., Ltd.

Claims (5)

[Claims] 1. A transmitter for transmitting alert information of various security sensors by radio wave radio signals, and a receiver for receiving the radio wave radio signals transmitted by the transmitter and demodulating the alert information. In the wireless security system, the radio wave signal for monitoring the transmission status is transmitted periodically. One transmission frequency is used for regular transmission, and multiple transmission frequencies are used for transmission of alert information. A wireless security system characterized in that a transmitter is provided with means for transmitting alert information by radio frequency radio signals. 2. A plurality of receiving antennas, an antenna switching means for sequentially and cyclically connecting the receiving antennas to be used for connection, and a receiving frequency switching for cyclically setting a receiving frequency corresponding to each transmitting frequency of the transmitter. The wireless security system of claim 1, wherein the receiver comprises means. 3. The wireless security system according to claim 2, wherein each reception frequency is switched and set during a connection period of each reception antenna. 4. The wireless security system according to claim 2, wherein each receiving antenna is switched and connected during a setting period of each receiving frequency. 5. A receiver mixes a received signal and an oscillated signal from a local oscillating unit with a frequency conversion circuit to convert the oscillated signal into an intermediate frequency. A local oscillating unit is constituted by a plurality of separately generated crystal oscillators and means for switching and connecting the oscillation signals of these crystal oscillators to a frequency conversion circuit, and the crystal oscillators are sequentially switched to set the reception frequency by switching. The wireless security system according to claim 2.