JPH0714089A - Radio monitoring device and radio monitoring system - Google Patents

Abstract

PURPOSE:To provide a radio monitoring device and a radio monitoring system capable of extending communication distance, and simultaneously capable of preventing malfunction. CONSTITUTION:A judging part 10 is provided with an original oscillator 11 to a PN code generator 13 to generate an original oscillation signal (a) of frequency set beforehand, the original oscillation signal (b) of the frequency different from this, and a PN code (c), a frequency modulator 14 to generate a frequency modulated signal (d) by changing over the original oscillation signals (a) and (b) on the basis of the change of the PN code (c), a burst generator 15 to generate a burst signal (e) of the frequency of the original oscillation signals (a) and (b) from the frequency modulated signal (d), and send the burst signal (e) to an antenna 16, a synchronous detector 17 to detect a received signal from the burst signal generator 15 on the basis of the frequency modulated signal (d), and a low pass filter 18 and a processing display device 19 to judge the opening and closing state of a switch 22 by detecting whether a detected signal (h) from the synchronous detector 17 contains the frequency of the original oscillation signals (a), (b) or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless monitoring device and a wireless monitoring system used for monitoring the status change of monitored objects such as doors, windows and keys.

[0002]

2. Description of the Related Art Some wireless monitoring devices include a response unit attached to an object to be monitored and a determination unit that wirelessly communicates with the response unit to monitor a change in the state of the object to be monitored.
Further, in some wireless monitoring devices, the response unit operates without a power source.

In a wireless monitoring device that operates without a power source, the response unit resonates with the frequency of the received signal generated by receiving the radio wave from the determination unit. Then, the response unit uses this resonance to send an echo wave (reflected wave) to the determination unit. At this time, whether to send an echo wave is controlled depending on the state of the monitored object.

An example of this wireless monitoring device is Japanese Patent Laid-Open No. 3-11.
It is shown in Japanese Patent No. 8691.

With such a wireless monitoring device, it is possible to check the open / closed state of, for example, a door or a window by a determination unit installed at a remote place. Moreover, since the response unit attached to the door or the window operates without a power source, wiring for the power source is not required in the door or the window.

[0006]

By the way, in the above-described radio monitoring apparatus, since the response section generates an echo wave by resonance and sends it to the determination section, if there is a similar apparatus in the same communication area. , They interfere with each other and cannot communicate. Further, the wireless monitoring device described above is vulnerable to noise, and if the distance between the determination unit and the response unit is long, the wireless monitoring device is easily affected by noise and the possibility of malfunction increases.

An object of the present invention is to provide a wireless monitoring device and a wireless monitoring system which can extend the communication distance and prevent malfunctions by eliminating such drawbacks.

[0008]

According to the present invention, a judging section includes a first antenna for radiating an input burst signal as a burst wave, a second antenna for receiving the burst wave and generating a reception signal, and a receiving antenna for receiving the burst wave. It is inserted between the resonance means that resonates with a signal and causes the signal generated by this resonance to be radiated from the second antenna as an echo wave to the first antenna, and the second antenna and the resonance means. In a wireless monitoring device having a response unit that includes a switch that opens and closes, a determination unit is configured to generate a first signal having a preset frequency, a second signal having a frequency different from that of the first signal, and a first pseudo noise code. The generating means, the modulating means for switching the first signal and the second signal based on the change of the pseudo noise code to generate the frequency modulated signal, and the first signal and the second signal from the frequency modulated signal. Second generation means for generating a burst signal of the frequency of the signal and transmitting the burst signal to the first antenna, detection means for detecting the reception signal from the first antenna based on the frequency modulation signal, and detection from the detection means. And a determination unit that determines whether the switch is open or closed by detecting whether the signal includes the frequencies of the first signal and the second signal.

In the radio monitoring apparatus of the present invention, the first generating means repeatedly generates "1" and "0" to generate a pseudo noise code.

The present invention is a wireless monitoring system in which a plurality of the above wireless monitoring devices are installed in the same communication area,
Each first generating means respectively generates a different m-sequence pseudo-noise code.

The present invention provides a wireless monitoring system in which a plurality of the above wireless monitoring devices are installed in the same communication area,
Each first generating means generates a different Gold code as a pseudo noise code.

The present invention provides a wireless monitoring system in which a plurality of the above wireless monitoring devices are installed in the same communication area,
Each first generation means has changed the division ratio of at least one of the first signal, the second signal and the pseudo noise code.

The present invention is a wireless monitoring system in which a plurality of the above wireless monitoring devices are installed in the same communication area,
Each of the first generating means generates a pseudo noise code in synchronization with a commercial power supply that drives the determination section.

[0014]

In the wireless monitoring device according to the present invention, the determination unit is the first
The burst signal having the frequency of the signal and the frequency of the second signal is sent to the response unit as a burst wave.

When the switch of the response unit is in the closed state, the response unit sends the echo wave based on the burst wave from the determination unit to the determination unit, and does not send the echo wave when the switch is in the open state. At this time, since the burst wave from the determination unit includes the frequency of the first signal and the frequency of the second signal, the echo wave also includes these two frequencies.

Upon receiving the echo wave, the judging section detects the received signal and generates a detected signal. The determination means determines the open / closed state of the switch of the response unit based on whether or not there is a signal of the frequency of the first signal and a signal of the frequency of the second signal in the detected signal.

Further, in the wireless monitoring system of the present invention,
Since the determination unit generates an m-sequence pseudo-noise code, a Gold code, or a pseudo-noise code in which at least one of the first signal, the second signal, and the pseudo-noise code has a different frequency division ratio, Different burst waves are assigned to the wireless monitoring devices installed in the.

Further, according to the wireless monitoring system of the present invention, the determination unit of each wireless monitoring device generates a pseudo noise code in synchronization with the commercial power source.

[0019]

Embodiments of the present invention will now be described with reference to the drawings.

[First Embodiment of Radio Monitoring Apparatus] FIG. 1 is a block diagram showing a first embodiment of a radio monitoring apparatus according to the present invention. This wireless monitoring device includes a determination unit 10 that determines the open / closed state of a monitored object such as a door, a window, a key, and a crescent, and a response unit that is attached to the monitored object and communicates with the determination unit 10 by magnetic field coupled communication. And 20.

The determination unit 10 includes the original oscillators 11, 12 and PN.
A code (pseudo-noise code) generator 13, a frequency modulator 14 as a modulating unit, a burst generator 15 as a second generating unit, an antenna 16 as a first antenna, a synchronous detector 17 as a detecting unit, a low-pass filter ( LPF) 1
8 and a processing / display device 19. In the first embodiment, the first generating means is the original oscillators 11 and 12 and the PN code generator 1.
3 and 3.

The response unit 20 also includes an antenna 21 as a second antenna, a switch 22, and a solid resonator 23 as a resonance means.

The original oscillator 11 has a preset frequency.
Wave number f₁The pulse-shaped original oscillation signal a of
Send to the adjuster 14. The original oscillator 12 is the frequency of the original oscillation signal a.
Number f ₁Different frequency f₂The pulse-shaped original oscillation signal b of
It is shaken and sent to the frequency modulator 14. PN code generator 13
Is a pulse train in which "1" and "0" are irregularly combined.
PN code c is generated and sent to the frequency modulator 14.

The frequency modulator 14 uses the burst generator 15 to generate the original oscillation signal a at the "1" portion of the PN code c, for example.
, And the original oscillation signal b is sent at the "0" portion. That is, the frequency modulator 14 generates a frequency modulation signal d obtained by frequency-modulating the PN code c and sends it to the burst generator 15.

The burst generator 15 outputs the frequency modulation signal d in a predetermined cycle for a predetermined time. That is,
The burst generator 15 generates a burst signal based on the frequency modulation signal d and sends the burst signal e to the antenna 16.

The antenna 16 transmits and receives the magnetic field component of electromagnetic waves. That is, the antenna 16 is the burst generator 1
A burst signal f from 5 emits a burst wave f.
Further, an induced voltage is generated by electromagnetic induction of the echo wave g sent from the response unit 20, and the induced voltage is sent to the synchronous detector 17 as a reception signal.

The synchronous detector 17 detects the received signal by calculating the product of the received signal from the antenna 16 and the frequency modulated signal d from the frequency modulator 14, and generates the detected signal h by this detection. . Then, the detection signal h is sent to the low pass filter 18.

The low-pass filter 18 removes high frequency components from the detected signal h and sends it to the processing / display unit 19.

The processing / display unit 19 is a low-pass filter 1.
The open / closed state of the monitored object is determined based on the detection signal from 8. That is, the processing / display device 19 includes the response unit 20.
This is determined by the presence or absence of the echo wave from. The processing / display unit 19 informs the determination result to the outside by, for example, turning on or off the light emitting diode or displaying a liquid crystal.

The antenna 21 of the response device 20 transmits and receives the magnetic field component of the radio wave in the same manner as the antenna 16.

The switch 22 is attached to an object to be monitored and opens / closes according to the change of the state. For example, switch 2
When attached to a door, 2 is open when the door is open and closed when the door is closed. And
In the closed state, the switch 22 directly connects the antenna 21 and the solid resonator 23.

The solid resonator 23 is composed of a crystal resonator, a ceramic resonator, or the like, resonates with a signal received from the antenna 21, and stores energy due to resonance. That is, the solid resonator 23 has a resonance frequency of about f _e to the frequency f _1, f _2. Then, the solid resonator 23 causes the antenna 21 to radiate the echo wave g with the stored energy.

Next, the operation of the first embodiment of this radio monitoring apparatus will be described with reference to the waveform chart of FIG.

The determination section 10 generates a frequency modulation signal d based on the original oscillation signal a from the original oscillator 11, the original oscillation signal b from the original oscillator 12, and the PN code c from the PN code generator 13. The burst generator 15 sends the frequency-modulated signal d to the antenna 16 for a time T at each start of "1" and "0" of the PN code c, for example. That is, a burst signal e is generated from the frequency modulation signal d,
Send to the antenna 16. The antenna 16 uses the burst signal e
To transmit a burst wave f into the air. At this time, the antenna 16 transmits a magnetic field component.

Upon receiving the magnetic field from the antenna 16, the antenna 21 of the response device 20 generates an induced voltage as a reception signal. At this time, if the door to be monitored is closed, the switch 22 sends the reception signal from the antenna 21 to the solid state resonator 23. The solid resonator 23 resonates with this received signal, and the antenna 21 transmits a magnetic field component as an echo wave by this resonance. That is, the echo wave g is transmitted between a group of pulses of the burst signal e.

Upon receiving the echo wave g, the antenna 16 of the determination device 10 sends the induced voltage to the synchronous detector 17 as a received signal. The synchronous detector 17 detects the received signal by calculating the product of the received signal from the antenna 16 and the frequency modulation signal d, and generates the detected signal h. At this time, the detection signal h is a signal obtained by periodically arranging signals based on the frequency f ₁ and the frequency f ₂ . The low pass filter 18 is
The low frequency component of the detection signal h is sent to the processing / display unit 19. Processing and display unit 19, according to the echo from the decision unit 10, a signal of a frequency f ₁ -f _e, since the signal of the frequency f ₂ -f _e periodically exist, the switch 2 of the response device 20
2 is in the closed state.

As described above, in the first embodiment, since the burst signal e includes two frequencies, the influence of noise can be reduced.

[Second Embodiment of Radio Monitoring Apparatus] Radio Monitoring Apparatus
In the second embodiment, the PN code generator 13 of the first embodiment is
As shown in 3, PN that repeats "1" and "0" alternately
Code c₁To the burst generator 15. As a result, the bar
The strike generator 15 has a frequency f₁And frequency f₂Alternating with
Frequency-modulated signal d continues₁Generate a burst generator 1
5 is the frequency f₁And frequency f ₂Burst that alternates with
Signal e₁To occur.

According to the second embodiment, the PN code generator 13
Generates a PN code c ₁ that alternately repeats "1" and "0", so that the configuration of the PN code generator 13 can be simplified.

[First Embodiment of Radio Monitoring System] FIG.
It is a block diagram which shows Example 1 of the wireless monitoring system which concerns on this invention. In this wireless monitoring system, two wireless monitoring devices of the first embodiment (FIG. 1) are installed in the same communication area. In the first embodiment of the wireless monitoring device, the wireless monitoring device has the same configuration as that in FIG. 1, and therefore the same reference numerals as in FIG. 1 are used.

In this radio monitoring system, the PN code generator 13 of the determination unit 10 ₁ uses the m-sequence code as the PN code. This m-series code is the code with the maximum length among the codes generated using a plurality of registers and an arithmetic circuit.

The determination unit 10 ₁ generates a frequency modulation signal based on the m-sequence PN code, further generates a burst wave f ₁ from this frequency modulation signal and sends it to the response unit 20 ₁ .

When the decision section 10 ₁ receives the echo wave g ₁ from the response section 20 ₁ , the decision section 10 ₁ detects the received signal by using the m-sequence frequency modulation signal. Then, the open / closed state of the switch 22 of the response unit 20 ₁ is determined based on the detected signal.

The PN code generator 13 of the other decision unit 10 _2.
Generates an m-sequence PN code different from that of the determination unit 10 ₁ . The determination unit 10 ₂ sends the burst wave f ₂ generated based on this PN code to the response unit 20 ₂ .

The determination unit 10 ₂ receives an echo wave g ₂ from the response unit 20 _2, it detects the received signal using a frequency-modulated signal by the determination unit 10 ₁ and the different m-sequence, the switch 2
The open / closed state of 2 is determined.

[0046] The determination unit 10 ₂ also receives the echo wave g ₁ from the response unit 20 _1, the frequency modulation signal used when the detection is different, not be detected by the synchronous detector 17. As a result, since the determining unit 10 ₁ and the determining unit 10 ₂ respectively use different m-sequence PN codes, it is possible to know the open / closed state of the response unit of the own device.

In the first embodiment of the wireless monitoring system,
I installed two wireless monitoring devices in the same communication area,
The number of wireless monitoring devices to be installed is not particularly limited to this. At this time, each device may generate an m-sequence PN code unique to the device itself.

[Second Embodiment of Wireless Monitoring System] In this wireless monitoring system, the determination unit 1 of the wireless monitoring system shown in FIG. 4 is used.
Instead of the m-sequence PN code generated by 0 ₁ and 10 ₂ , a Gold code is used. The gold code is
It is a code created by combining two m-sequence codes of the same length. Many different codes can be generated by combining two m-sequence codes and changing the phase between the codes.

By using the Gold code, this wireless monitoring system can install a larger number of wireless monitoring devices in the same communication area as compared with the first embodiment of the wireless monitoring system.

[Third Embodiment of Wireless Monitoring System] In this wireless monitoring system, the determination unit 1 of the wireless monitoring system shown in FIG. 4 is used.
The period of the original oscillation signals generated by the original oscillators 11 and 12 of 0 ₁ and 10 ₂ and the time T (FIG. 2) at which the burst generator 15 outputs the frequency modulation signal are changed. That is, the division ratio of these signals is changed. Thereby, each determination unit 10
_The burst signals generated by ₁ and 10 ₂ can be different,
Multiple wireless monitoring devices can be installed in the same communication area.

[Fourth Embodiment of Radio Monitoring System] This radio
In the monitoring system, the wireless monitoring system of FIG.
10₁The burst generator 15 of the
Generates a PN code. That is, as shown in FIG.
Time T from the start of each cycle of commercial power₁Time point
t₁, T ₂, T₃PN code is generated at the timing like
To do. Judgment unit 10₂Generate PN code in the same way
To do.

[0052] Thus, the timing determination unit 10 ₁ generates a PN code, the determination unit 10 ₂ and the timing for generating the PN code match, the determination unit 10 ₁ and the determination unit 10 ₂ is synchronized A PN code can be generated.

[0053]

As described above, according to the radio monitoring apparatus of the present invention, the judging section transmits the burst wave generated by using the pseudo noise code and the first signal and the second signal of two different frequencies. Since the response unit transmits an echo wave in response to the burst wave, the burst wave and the echo wave are less susceptible to external noise during transmission. As a result, the occurrence of malfunction can be reduced.

Further, according to the wireless monitoring system of the present invention, even if a plurality of wireless monitoring devices are installed in the same communication area, the respective wireless monitoring devices generate different burst waves, so that they can be prevented from interfering with each other. .

Further, according to the wireless monitoring system of the present invention, since each wireless monitoring device within the same communication area generates a burst wave in synchronization with the commercial power source, each device can operate in synchronization.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a wireless monitoring device of the present invention.

FIG. 2 is a waveform diagram of the first embodiment.

FIG. 3 is a waveform diagram of a second embodiment of the wireless monitoring device of the present invention.

FIG. 4 is a block diagram showing a first embodiment of the wireless monitoring system of the present invention.

FIG. 5 is a diagram showing synchronization with a commercial power supply.

[Explanation of symbols]

 10 Judgment Unit 11 Original Oscillator 12 Original Oscillator 13 PN Code Generator 14 Frequency Modulator 15 Burst Generator 17 Synchronous Detector 18 Low Pass Filter 19 Processing / Display a Original Oscillation Signal b Original Oscillation Signal c PN Code d Frequency Modulation Signal e Burst signal

Claims (6)

[Claims] 1. The determination unit includes a first antenna that radiates an input burst signal as a burst wave, and a second antenna that receives the burst wave and generates a reception signal and resonates with the reception signal and It is inserted between a resonance unit that causes a signal generated by resonance to be radiated from the second antenna as an echo wave to the first antenna, and is inserted between the second antenna and the resonance unit, and opens and closes according to a change in the state of the monitored object. In a wireless monitoring device including a switch as a response unit, the determination unit is configured to generate a first signal having a preset frequency, a second signal having a frequency different from that of the first signal, and a pseudo noise code. Generating means, modulating means for generating a frequency modulated signal by switching between the first signal and the second signal based on a change in the pseudo noise code, and the frequency modulated signal Et al., The first signal and the second
Second generating means for generating a burst signal having a signal frequency and transmitting the burst signal to the first antenna; detecting means for detecting a received signal from the first antenna based on the frequency modulated signal; A wireless monitoring device, comprising: determination means for determining whether the detection signal from the means includes the frequencies of the first signal and the second signal to determine the open / closed state of the switch. 2. The radio monitoring apparatus according to claim 1, wherein the first generation unit repeats "1" and "0" to generate the pseudo noise code. 3. A wireless monitoring system in which a plurality of wireless monitoring devices according to claim 1 are installed in the same communication area, wherein each of the first generating means generates a different m-sequence pseudo noise code. And wireless monitoring system. 4. In a wireless monitoring system in which a plurality of wireless monitoring devices according to claim 1 are installed in the same communication area, each of the first generating means generates a different Gold code as the pseudo noise code. A characteristic wireless monitoring system. 5. In a wireless monitoring system in which a plurality of wireless monitoring devices according to claim 1 are installed in the same communication area, each of the first generating means includes the first signal, the second signal and the pseudo noise code. The wireless monitoring system is characterized in that at least one of the frequency division ratios is changed. 6. A wireless monitoring system in which a plurality of wireless monitoring devices according to claim 1 are installed in the same communication area, wherein each of the first generating means synchronizes with the commercial power source that drives the determining section. A wireless monitoring system, wherein each wireless code is generated.