SU455354A1 - Alarm device - Google Patents

Description

one

The invention relates to alarm devices and can be used to protect the perimeters of various objects and buildings from intruder intrusion.

Alarm devices are known that contain a series-connected generator, a signal measurement unit with connected sensing elements, a detector, a high-pass filter, and a normal unit, one output of which is connected to the same input of the coincidence circuit loaded on the executive head.

In the known devices, changing the parameters of the sensing elements causes a signal at the output of the signal measurement unit, which, after passing the detector, high pass filter, threshold unit, coincidence circuit, is fed to an execution unit that supplies an alarm signal.

However, such devices, which have relative noise immunity to climatic noise (rain, speg), produce a large number of false alarms under conditions affecting the sensitive elements of the grass, branches of bushes and trees, and a sharp rain front. The noise at the exit of the threshold disturbance from the above interferences considerably exceeds the trigger level and

lies in the bandwidth of the sensor alarm systems.

The purpose of the invention is to increase the reliability of the device.

This is achieved by introducing a linear adjustment unit for the threshold of operation at an average level of 0 and sequentially connected a time selector of pulses and before the OL an electric generator. The input of the linear adjustment unit of the threshold of operation and the average noise level of the Ace to the output of the high-pass filter, and to the output of the high-pass filter. to the block, the INPUT of the pulse selector is connected to the other output of the i-block, and additionally to the second input to the second inputs of the coincidence circuit.

The drawing is a block diagram of the proposed device.

It contains a generator 1, a block 2 of measuring signal parameters with two sensitive elements and 3 i 4, filter 5 radio ex, amplifier 6 high frequency, phase) detector 7, filter B of high frequencies, amplifier 9 direct current, filter 10 lower frequency, subtracting the device 11, the threshold unit 12, the difference I feel about the circuit 13, the pulse polarity selector 14, the one-shot 15, the coincidence circuit 16, the polarity selector 17 or pulses, the inverter 18, the additional generator 19, the coincidence circuit 20, the execution unit 21, rectifier 22, selector 23 max amp amplitude, multpvibrator 24 .in the start-stop mode.

The linear adjustment unit 25 is triggered, but the average level consists of an amplifier 9 of a constant-current current, a low-pass filter 10 and a subtractor 11. The temporal selector 26 of pulses contains diffracting day 13, the selector 14 of polarity of nmulse, the oscillator 15, the I and F scheme, the selector 17 no.p rpstn pulses and inverter 18.

The device works in the following way.

Generator 1 is driven by block 2 of measured signal parameters with connected sensors 3 and 4, forming a double line to create a useful signal consisting of a combination of two pulses and a pause between them. A change in the sensing elements caused by a person’s approach or a change in climatic conditions is converted by a signal measuring unit into a corresponding signal whose frequency is equal to the frequency of the generator 1 supplying the measuring circuit, and this signal contains both active and reactive components that are out of phase relative to each other. friend at 90 °.

Next, the signal passed through the radio interference filter 5, the high-frequency amplifier 6, and enters the phase detector 7, the onboard voltage, the voltage of which is removed from generator 1. The phase angle between the carrier frequency and the reference voltage is set so that the output of the phase detector is only reactive signal component.

After detection, the signal is coupled to a high-pass filter 8, which cuts off the component due to the slow variation of the parameters of the sensing elements due to climatic influences. After that, the signal is amplified by an amplifier of a constant-current current, one output of which is connected to the input of the subtractor 11 directly, the other through the low-pass filter 10, and then goes to the threshold unit 12. These nodes (amplifier of the positive current, subtraction, filter low frequency) form the block automatic adjustment of the norm response (ARPS). It is intended to control the continuous sequences of interfering impulses arising at the output of the direct current amplifier from influencing sensitive elements of a sharp rain front, grass oscillations, branches of bushes and trees, since the signals from this type of interference lie in the passband of the device.

Tension shchuma, occurring at the output of the amplifier 9 direct current, in the form of a sequence of pulses is fed to one input of the subtractor 11 through the forward channel, PA another input of the subtractor

the device through the low-pass filter 10 gets the average level of voltage schuma. Pa subtracting the device the average level of Н1ум, subtracted from the noise channel of the channel, moves it away from the trigger threshold. The higher the intensity of the schum and the interference pulses and the continuous following one another, the better the ARPS works.

A useful crib containing a combination of two pulses and a pause between a person and a person arises between the sensitive elements, receives a subtraction input, his device 11 does not pass to the other (this is determined by the frequency response of the low-pass filter), and, superimposed on Iium, triggers the trigger unit 12.

The threshold unit generates two rectangular-shaped pulses from the useful signal.

which follow further on to differential H1, the th center, where their fronts are converted into pulses of positive and negative polarity. A negative (positive) pulse from the front of the first pulse of the useful signal is fed to the selector 14 of negative (positive) pulses. The generated negative (positive) pulse at the selector output triggers a one-shot 15, which will give a signal with a maximum duration post max passing through one of the inputs of the common mode 16. At the same time, a pulse from the output of the selector 14 is applied to one of the inputs of the matching circuit 20. After expiration

the leading edge of the pulse of a useful signal. that, immediately at the output of the selector 14 disappears.

The positive (negative) imiuls from the falling edge of the first pulse of the signal.ch arrives at the selector 17 of the positive (negative) pulses and then to the inverter 18, from the inverter output to the second input of the matching circuit 16, at the nerve input of which there is already a pulse

from the one-shot 15. Next, the coincidence circuit 16 outputs a pulse to the input of the additional generator 19, which sets the time of the spin between the two pulses of the useful signal from the output of the threshold unit 12.

Pmpulse from the output of the auxiliary generator is present at the second input of the coincidence circuit 20, at the first input of which the pulse from the front of the first impulse of the useful signal

already missing. If during the pause time the second pulse of the useful sigpal appears at the output of the threshold device, then its leading edge, having passed the differentiating value 13 and the pulse selector 14, will be

The first input of the coincidence circuit 20, which gives an alarm pulse to the input input and the opposing unit 21, with an audible or ontic alarm indicator.

Thus, single Schum pulses with steep fronts that pave the ARPS due to its inertia are filtered out of the useful signal by the pulse selector. An additional generator 19 and a matching circuit 20 select a pause for a combination of two pulses. The design of the signal enclosure containing the sensitive elements makes it possible to set stable temporal parameters of the useful signal for accurate operation of the device, when the pair, breaking the first signal band, falls into the zone of action of the second center-line leaf during time T, ..., U. In the case of a ground or accidental short-circuit of the signal fence on the ground, an increase in the leakage conductivity of the signal fence to a certain critical value, the signal from the high-frequency amplifier 6 through the rectifier 22 enters the maximum amplitude selector 23. Upon reaching a certain amplitude of the input signal, the selector 23 starts the multivibrator 24 located in the start-stop mode. By periodically closing and opening the contacts of the executive unit 21, it is possible to judge the failure of the signal fence. memory and 3 The device for alarming, containing a sequence of connected generator, a unit for measuring the parameters of a signal with keyed-off sensors, a detector, a filter of frequency and a threshold unit, one of which is connected to one input coincidence circuits loaded on the performer 1 block 1, og.tchaugtsses that, in order to make reliable a6oTiii device. A nopoia adjustment unit with a single P1uma level and successively connected time selector pulses and an additional generator are entered into it, the input of the linear adjustment unit of the response threshold by the average noise level is connected to the output of the high-pass filter, and the output is connected to the threshold unit, the input of the pulse selector connected to another output of the threshold unit, and the output of the additional generator is connected to the second input of the matching circuit.

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