JPH03163698A - Radio wave alarming device - Google Patents

Abstract

PURPOSE:To decide an invader by two variables, i.e. its size and movement, and to improve detecting accuracy by detecting the invader based upon an attenuation area to be the produce of the attenuance of a received wave in a guard area and an attenuation generating time. CONSTITUTION:A microwave from a transmission part 1 is received by a receiving part 2, the received wave is compared with a prescribed attenuation value by a level drop detector 25, and when the level of the received wave is dropped less than the prescribed value, a timer generator 26 is started. The generator 26 outputs timer pulses to an attenuation area calculating means 20 for a prescribed time. The timer pulse generating period is set up to a value slightly longer than an average time required for a prostrating invader to cross the guard area. In the means 20, a counter circuit 28 counts up a peak voltage corresponding to a clock signal generated from a peak voltage generator 27 to find out an attenuation area value. When the attenuation area value is large than a value previously set up in a threshold setting circuit 32, a deciding circuit 29 decides the existence of an invader. Consequently, a small animal or the like can be discriminated indepenently of the posture or the like of the invader and the detecting accuracy can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a radio wave transmitting section and a radio wave receiving section in opposing arrangement within a predetermined security area, and uses radio waves radiated within the same area to control the security area. Detects the presence or absence of intruding objects, including intruders,
The present invention relates to a radio wave alarm device of a counter-blocking type that issues an alarm when an intrusion is detected, and particularly relates to a radio wave alarm device that detects an intruder from the magnitude of an attenuation area value obtained as an integrated value of the amount of decrease in the level of received radio waves and time.

[Prior art]

Various intruder detection methods using radiated radio waves have already been proposed, but in general, when the received level drops below a predetermined value compared to the radio wave level transmitted within the security area, the radio network is activated. A radio wave alarm system is used that detects the occurrence of an intruder within the same area and issues an alarm.

[Problem to be solved by the invention]

However, in this conventional method, when an intruder, for example, passes through the radio wave network between the transmitting unit and the receiving unit in a standing position, and when it passes through the same radio wave network in a crawling position, the reception is difficult. Since the degree of attenuation of radio waves differs greatly, a predetermined detection level value regarding the attenuation value must be set so that it can be detected in either case. Therefore, in this type of method, the predetermined detection level value is set to a relatively low value in order to match the low-attenuation crawling posture, and as a result, if a dog or cat accidentally passes through the security area. is also detected as an intruder,
The problem is that it may cause an alarm.

Now, considering the security area using radio waves as described above, when a person passes through the security area in a crawling posture,
Although the degree of attenuation of the received radio waves is small, on the other hand, since the intruder is in a crawling position, the passage time when moving within the security area is longer, and if the intruder runs in the running position and passes through the security area, the passage time will be longer. is shorter, but the degree of attenuation is greater. Furthermore, when a small animal such as a dog or cat passes through and blocks the radio wave network in a security area, attention can be paid to the phenomenon that the attenuation level is small and the passage time is short.

Therefore, an object of the present invention is to define an attenuation area amount based on the product of the degree of attenuation of received radio waves and the time at which attenuation occurs within a security area, and to detect intruders, intruders, and other intruding vehicles based on this attenuation area amount. The purpose of the present invention is to provide a radio wave alarm device that Hereinafter, the present invention will be explained based on examples.

[Means of solution and action]

According to the present invention, the present invention includes a transmitter that emits radio waves into the security area, and a receiver that is disposed opposite to the transmitter and receives the radio waves radiated from the receiver into the security area. , a radio wave alarm device of a counter-blocking type that determines the presence or absence of an intruder by monitoring the attenuation state of radio waves in a security area and issues an alarm indicating the presence of the intruder, wherein the receiving unit is configured to detect the received radio waves. a level detection means for comparing the degree of attenuation with a predetermined set value; and a attenuation area value for calculating the attenuation area value consisting of the product of the degree of attenuation and the duration of decay in response to the judgment of the degree of attenuation by the level detection means. calculating means, and comparing the attenuation area value calculated by the attenuation area value calculation means with a predetermined comparison reference value, and determining that there is an intruder in the security area when the attenuation area value exceeds the comparison reference value. The present invention provides a radio wave alarm device equipped with a discriminating circuit that determines whether a predetermined security space where radio waves are emitted is defined based on the attenuation area value defined by the product of the attenuation degree and time, and Since the presence or absence of an intruder that causes radio wave attenuation within the interior is determined, it is possible to determine the presence or absence of an intruder based on two variables, the size and movement of the intruder. Accuracy can be improved.

〔Example〕

FIG. 1 is a block diagram of a counter-blocking radio wave alarm device using microwaves according to the present invention, and FIG. 2 is a time chart for explaining the operation of the radio wave alarm device based on FIG. Further, FIG. 3 is a block diagram showing another embodiment of the opposing blocking type radio wave alarm device according to the present invention.

Now, referring to FIG. 1, in the area to be guarded (hereinafter referred to as the security area) that is common to the radio wave alarm device according to the present invention, a radio wave transmitter and a receiver are provided spaced apart from each other.
1 is a transmitter, and 2 is a receiver. The transmitter 1 includes a stabilized power supply circuit 11, a Gunn oscillator 12 that generates a predetermined microwave when a predetermined voltage is applied from the stabilized power supply circuit 11, and a Gunn oscillator 12 that outputs a pulse signal of, for example, 2 KHz to generate the microwave. It is equipped with a modulator 13 that modulates the amplitude of waves, and a transmitting antenna 14 installed at a suitable location within the security area to radiate the amplitude-modulated microwaves into the space of the security area. .

On the other hand, the receiving section 2 includes a receiving antenna 21, and this receiving antenna 2l is installed at a suitable location within the security area at a predetermined distance from the transmitting antenna 14. The microwave received by the receiving antenna 21 is transmitted to a bandpass filter 22, and the modulated wave component is identified by the bandpass filter 22 from the microwave radiated from the transmitter 1. The bandpass filter 22 is detected by a detector 23, and the detected signal is then amplified by a low frequency amplifier 24.

The receiving unit 2 is further provided with a level drop detector 25 that compares the output voltage of the low frequency amplifier 24 with a predetermined value and determines whether or not it is lower than the predetermined value. The generator 25 is excited by a stabilized power supply circuit 31, and when the level drop detector 25 determines that the output voltage of the low frequency amplifier 24 is lower than a predetermined value, the timer generator 26 is activated in response to the determination signal. starts and generates a timer signal. The timer generator 26 is connected and arranged so as to output a stop trigger pulse as an instruction signal for stopping the counter operation of a counter circuit 28, which will be described later, after a predetermined period of time has elapsed. Furthermore, the receiving section 2 includes
Attenuation area value calculation means 20 is provided, and the attenuation area value calculation means 20 includes a peak voltage detector 27, the above-mentioned counter circuit 28, and a clock signal generator 30.

The peak voltage detector 27 is connected to the low frequency amplifier 24 described above, and is activated when the level drop detector 25 determines that the output voltage of the low frequency amplifier 24 is below a predetermined value, and generates a clock signal. The voltage peak value at that point in time is detected in accordance with the clock signal of the device 30. The counter circuit 28 includes a peak voltage detector 2 as shown in the figure.
7 is a counter circuit that sequentially integrates peak values, and outputs the integrated value to a discrimination circuit 29, which will be described later.

The peak voltage detector 27 stops its operation when the timer generator 26 issues a stop signal after a predetermined time has elapsed, and on the other hand, the counter circuit 28 sends the integrated value to the discrimination circuit 29 using the stop signal. After that, clear the integrated value.

The determination circuit 29 reads out a predetermined value predetermined by the threshold value setting circuit 32, compares it with the integrated value of the counter circuit 28 of the attenuation area value calculation means 20, and determines that when the integrated value is larger than the predetermined value, It is determined that there is an intruder or an intruder into the security area, and an alarm signal is output to an alarm (not shown).

Next, the operation of this embodiment will be explained based on the time chart of FIG. As mentioned above, the transmitting antenna 14 of the transmitter 1
A microwave whose amplitude is modulated at approximately 2 kHz is transmitted from the oscilloscope. At this time, the receiving section 2 receives the microwave modulated as described above through the receiving antenna 21, and sends it to the level drop detector 25 via the bandpass filter 22, the detector 23, and the low frequency amplifier 24. . Level drop detector 25
In , the human-powered microwave radio signal T is compared with a predetermined attenuation value a (detection level value a in Figure 2), and when it is lower than the predetermined attenuation value a, it is detected as shown in Figure 2 (A). A start pulse P shown in is output to the timer generator 26, and the timer generator 26 is activated. At this time, the activated timer generator 26 generates a stop pulse P, as shown in FIG. 2(C), after a predetermined time Tr (generation time of timer pulse P3) has elapsed, as shown in FIG. 2(C). After outputting to the counter circuit 28 and sending the integrated value of the counter circuit 28 to the discrimination circuit 29, the integrated value is cleared. Here, the predetermined time Tr is set to be slightly longer than the average time required for an intruder to cross the security area in a crawling position.

When a person crosses a security area in a standing position, the passing time is short, but the degree of attenuation is large, so the attenuation area is large.For small animals, the degree of attenuation is small, so the attenuation area is small. Become. The peak voltage detector 27 always receives a clock signal from the clock signal generator 30, and responds to the clock signal during the generation time Tr of the timer pulse P2.
A peak voltage value corresponding to the sampling width of the clock signal as shown in FIG. 2 is detected from the microwave radio signal T of the low frequency amplifier 24. A signal corresponding to the detected peak value is output from the peak voltage detector 27 to the counter circuit 28, and the counter circuit 28 adds up the counts. This count value becomes the product of the attenuation degree and the attenuation time, that is, the attenuation area value.

In the determination circuit 29, the attenuation area value is compared with a predetermined value set in advance by the threshold value setting circuit 32, and when it is larger than the predetermined value, it is determined that an intruder is present. the result,
Discrimination circuit 29 outputs an alarm signal. Note that since the predetermined value set in this threshold value setting circuit 32 can be variably adjusted,
It can be adjusted each time depending on the installation conditions of this radio wave alarm device.

Next, another embodiment of the radio wave alarm device according to the present invention will be described based on FIG. Note that in FIG. 3, the same numbers as in FIG. 1 indicate the same electrical elements or parts. The difference from the structure of the embodiment shown in FIG. 1 lies in the internal structure of the receiving section 2. That is, in the embodiment shown in FIG. 3, the level drop detector 40 is composed of two elements, an excess detector 41 and a return detector 42. When the voltage exceeds a predetermined value, a starting pulse is output to the peak voltage detector 51. Is the return detector 42? When the Ja decay exceeds a predetermined value and returns to below the predetermined value, a stop pulse is output to both the peak voltage detector 51 and the counter circuit 52. The peak voltage detector 51 detects the peak voltage in the received microwave radio wave in response to the clock pulse from the clock signal generator 53, as described above, and outputs the peak voltage to the counter circuit 5.
Output to 2. The counter circuit 52 integrates the peak values. Upon receiving the stop pulse from the return detector 42, the counter circuit 52 outputs the integrated value to the discrimination circuit 29 and clears the gtW value.

The determination circuit 29 reads out a predetermined value from the threshold value setting circuit 32 as described above, and compares the predetermined value with the count value to determine the presence or absence of an intruder. Alternatively, as another embodiment, if the presence or absence of an intruder is to be determined as quickly as possible, the determination circuit 2
9, and before receiving the stop pulse from the return detector 42, the presence or absence of an intruder may be determined.

〔Effect of the invention〕

As described above, the present invention defines an attenuation area value based on the product of the attenuation degree value by which the radio wave network radiated to a predetermined security area is attenuated by an intruder and the attenuation duration time, and this attenuation area value is set to a predetermined value. When the comparison result exceeds a predetermined value, it is determined that there is an intruder or an intruding object such as an intruding vehicle, so a small animal that is not considered an intruder may accidentally fall into the security area. Even if the user enters the room, it is not determined that there is an intruder, and therefore malfunctions of the radio wave alarm device can be eliminated and reliability can be improved. Further, by digitally processing the radio wave signal inputted to the attenuation area value calculation means, the determination accuracy of the discriminator circuit is improved and the circuit design becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a counter-blocking radio wave alarm device using microwaves according to the present invention, FIG. 2 is a time chart diagram for explaining the operation of the radio wave alarm device based on FIG. 1, and FIG. FIG. 3 is a block diagram showing another embodiment of the opposite blocking type radio wave alarm device according to the invention. DESCRIPTION OF SYMBOLS 1... Transmitting section, 2... Receiving section, 14... Transmitting antenna, 20, 50... Attenuation area value calculation means, 21...
・Receiving antenna, 25...Level drop detector, 26・
・・Timer generator, 27・・Peak voltage detector, 28・
... Counter circuit, 29 ... Discrimination circuit, 30 ... Evening lock signal generator, 32 ... Threshold value setting circuit, 40 ...
・Level drop detector.

Claims (1)

[Claims] 1. A transmitter that emits radio waves into the security area, and a receiver that is disposed opposite to the transmitter and receives the radio waves radiated from the transmitter into the security area. In a radio wave alarm device of a counter-blocking type that monitors the attenuation state of radio waves in a security area to determine the presence or absence of an intruder and issues an alarm to notify of the intruder, the receiving unit is configured to detect the received radio waves. level detection means for comparing the degree of attenuation with a predetermined set value; and attenuation area value calculation for calculating a attenuation area value consisting of the product of the degree of attenuation and the decay duration time in response to the judgment of the degree of attenuation by the level detection means. and comparing the attenuation area value calculated by the attenuation area value calculation means with a predetermined comparison reference value, and detecting that there is an intruder in the security area when the attenuation area value exceeds the comparison reference value. A radio wave alarm device characterized by comprising a discrimination circuit for discriminating. 2. The attenuation area value calculation means is responsive to the judgment of the degree of attenuation by the clock signal transmitter and the level detection means, and calculates the peak value in the received radio wave input in response to the clock pulse from the clock signal transmitter. 2. The radio wave alarm device according to claim 1, comprising: a peak voltage detector for detecting the peak voltage detector; and a counter circuit for cumulatively counting the peak value of the peak voltage detector.