SU798932A1 - Alarm - Google Patents

Description

one

The invention relates to automobiles, in particular, to an alarm system, and can be used to protect buildings, structures and individual objects, as well as to monitor vehicles and the like.

 An alarm device is known in which a change in the capacitance of a sensing element converts to a change in the frequency of the generator as the intruder approaches.

The voltage from the generator output is fed through a limiter, eliminating the influence of the parasitic amplitude change on the key, which forms a pulse sequence. Then the pulse sequence is differentiated, the pulse fronts are selected by the polarity selector, and the demodulators convert the change in frequency in a certain time interval into a change in amplitude.

The received signal is filtered and fixed by the executive unit.

one.

A capacitive intrusion detection system is also known.

In this system, the sensitive element is the skin of the aircraft or the signal fence of the wire. The sensing element and the ground form a capacitor which is connected to the circuit of the reference current source. The capacitor voltage varies in proportion to the magnitude and rate at which the capacitance of the sensing element is acquired at the approach of the intruder. This change

0 voltage is converted to a change in the duration of the time intervals that set the mode of operation of the reversible counter for the addition and subtraction of the counting pulses arriving

5 from the generator of the etching frequency. The contents of the reversing counter are decoded and fed to an alarm unit that generates a light and sound alarm signal G2.

0

The disadvantages of these devices are the appearance of false alarms during slow changes in the active component of a capacitor formed by a sensitive element and ground, the absence of alarms at certain ratios of measurement intervals and the speed of movement of an intruder, and the detection of only a moving one}

0 violator.

The closest in technical essence to the present invention is a device for protecting objects in the form of objects or rooms, containing sensitive elements by the number of monitored objects, connected via a KOMNiytat to the generator input, code converter, alarm unit and signaling device.

In this device, the switch for a certain period of time connects alternately sensitive elements to the generator circuit. If an intruder appears in the zone of action of any sensitive element, then the generator lacTOTa changes and enters the detector. The detector converts a change in frequency into a change in amplitude, performs analog filtering, and flips the signal with a threshold device.

From the output of the signaling device, the alarm signal goes to the first input: the converter, the code, the second input of which is connected to the switch. Under the action of the signals that occur on the code converter, the alarm signal is converted into a position code uniquely cc. It corresponds to the number of the sensitive element recording the violation, which is displayed on the indicator board

.

The disadvantages of this device are the appearance of false alarms with slow changes in the parameters of the sensing elements under. the impact of environmental factors, the mass sensitivity of the device at the cutoff frequency limits of the low- and high-pass filters, the violator’s omission at the interrogation rate of sensitive elements above or below the violator’s movement speed, and the detection of only a moving intruder.

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

This goal is achieved due to the fact that a control key, a reference sensitive element, a synchronizer, two pulse shapers, a reversible counter, a delay element, a decoding unit, two memory blocks, and a code of the sensitive sensor element are connected to the device. with one of the inputs of the controlled key, the output of which is connected to the input of the generator, the output of which through the first pulse shaper is connected to the first input of the reversible counter, first the synchronizer output is connected to second inputs of the controlled switch

and a reversible counter and the input of the address code generator of sensitive elements, the second synchronizer output is connected to the second input of the switch, the third input of the reversible counter and the input of the second pulse generator, the output of which is connected to the first input of the first memory block of the memory and through the delay element to the fourth input of the reversible counter, the outputs of which are connected to a decoding unit, the output of which is connected to the second input of the first memory block, the output of which is connected to the first input of the second memory block, output The shapers of the address code of the sensing elements are connected to the third inputs of the switch directly and to the second inputs of the second memory block through a code converter, the outputs of the second memory block are connected to the alarm signaling unit.-,

FIG. 1 shows a block diagram of the device for alarm signaling; in fig. 2 - timing diagrams explaining the principle of operation of the device.

The structural diagram of the device contains the generator 1, the reference sensitive element 2, the sensitive elements 3 ... 3 |, the first driver of 4 pulses, the reversible counter 5, the synchronizer b, the control key 7, the driver 8 of the address code of sensitive elements, switch 9, a decoding unit 10, a second driver 11, a delay element 12, a first memory block 13, a second memory block 14, a code converter 15, an alarm block 16.

The device works as follows.

Generator 1 continuously generates harmonic oscillations, the frequency of which is selected depending on the desired conversion slope,

l

equal to

Pf - SF where d - the value of the frequency change

generator;

. L.С. - value of the increment of the capacitance of the sensitive element introduced by the object-violating. . or car. The magnitude d is a linear function of the capacitance of a capacitor formed by the reference sensor element 2 or one of the senses. body elements 3 ... 3, connected in turn to the generator circuit 1.

From the output of the generator 1, the oscillations are fed to the input of the first driver 4, which converts them into square pulses (Fig. 2ci) arriving at the counting input of the reversible counter 5. Synchronizer 6 generates paraphane sequences of right-angled pulses (Fig. 2cH, D) the duration of which is half the time of detection of T is chosen such that the change in the frequency l {during their operation, in the presence of an extraneous object, is much greater than the change in the frequency of the generator 1 due to the influence of other factors on structural elements. During the action of the pulses (Fig. 2d) of the sequence, through the control key 7, the reference sensitive element 2 is connected to the circuit of the generator 1, and the potential corresponding to the addition mode is set at the control input of the reversing counter 5. When this impulses (Fig. 2a), coming from the output of the first driver. 4, the counting input of the reversing counter 5 is counted by it and, therefore, after the impulses expire (Fig. 2cG), the number 2 / T in binary or any other code (and depending on the type of counter used) is recorded in the reversing counter 5 , which uniquely corresponds to the frequency of the generator 1 at the considered time. During the operation of the pulse sequence (Fig. 2-8), the reference sensitive element 2 is turned off - from the circuit of the generator 1. The shaper 8 of the code of addresses of the sensitive elements sequentially, with the arrival of each pulse of the sequence, generates number codes, for example, 0 ... 001 sensitive elements 3 (Lig.2) and controls the operation of the switch 9, by means of which the sensitive elements 3, for example 3, in accordance with the number code, are connected with to the generator 1. At these times, the control input of the reversible counter and 5 sets the potential corresponding to the subtraction mode. In this case, the number corresponding to the number of pulses received at its counting input from the output of the first driver 4 during the duration of the T / 2 pulse of the sequence (Fig. 2b) is subtracted from the number 2 / T recorded earlier in the reversible counter 5. If there is no foreign object near the sensing element 3, for example 32, then a zero number is recorded in the operation code of the reversible counter 5, due to the fact that the sensing elements are identical and are in the same conditions as the surrounding environment. Thus, the influence of meteorological conditions on the parameters of the reference sensing element 2 and the sensing elements 3 ... ... 3) is compensated in a reversible counter. Therefore, at the output of the decoding unit 10, deciphering the states of the reversible counter 5, a signal is formed (Fig. 2e) corresponding to the absence of a foreign object near the sensitive element Z. Xley near the sensitive element 3, for example 3 (Fig. 2e), foreign object, then the frequency of the generator 1 is reduced by the value of g and, therefore, in the reversible counter 5 after performing the subtraction operation, a number equal to: 2 2 is recorded (rl Ul {TT T) At the output of the decoding unit 10 a signal is formed ( F d. 2e), corresponding to the presence of a VIS of a foreign object near the sensing element 3. Upon termination of the pulses of the sequence (Lig. 2) acting on the second Shaper 11, short pulses are formed from their rear edges (Fig. 2), which are delayed by the delay element 12 for the time dC (Fig. 25) required for overwriting information from the outputs of the decoding unit 10 into the first memory unit 13. The delayed pulses return the reversible counter 5 to the zero state. In this way, information is recorded in the first memory block (FIG. 2x) corresponding to one of the situations considered. This information is fed to the first input of the second memory block 14, to the address inputs of which at the same time signals from the converter 15 are received. The code transformer reorganizes the code of the number (fig.) of the sensing element produced by the shaper 8 into the position code of the cell address, memory (fig. 2i.), under the action of which a rewrite of the information from the first memory block 13 in the second box G4 memory (Fig. 2k, a). Next, the detection process described above is repeated for each of the sensing elements. After a cycle of interrogation of all sensitive elements, the information stored in memory block 14 is updated according to the state of sensitive elements in the interval of the second interrogation cycle, etc.

Under the influence of signals coming from the outputs of the second memory block 14, the display indicator cell corresponding to the sensing element 3, which has an object and an acoustic alarm unit 16 is turned on, is flashed.

During the subsequent detection periods in accordance with the polling cycle, the device operates as described.

The proposed device provides high noise immunity, the constancy of the established sensitivity and the ability to record the presence of an intruder in the zone of action of sensitive elements.

Claims (3)

1. USSR author's certificate number 491970, cl. G 08 E 13/22, 1974. 2. Patent CIJA number 3.62ZD59,. cl. 340-258, pub. 1971. 3. For application FRG 2539501, cl. П 08 В 13/26, published. 1977 (prototype). 1g.