RU1817120C - Device for detecting illegal crossing of the frontier - Google Patents

Abstract

The invention relates to burglar alarms. An object of the invention is to improve detection accuracy. The device comprises transmitting 1 and receiving 2 radiating cables, a pulse transmitter 3, delay elements 4, a receiver 5, a range selector 6, an alarm signal supply unit 7, a detector 8, a clock driver 9. The device provides constant sensitivity regardless of the place of crossing the boundary, which allows you to choose a fixed optimal threshold for the alarm unit. The device determines the intersection with a given accuracy at a lower transmitter power. This is due to the fact that all signals pass the length of the boundary once. 2 ill.

Description

Figure 1

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The invention relates to burglar alarms.

The purpose of the invention is to improve the accuracy of detection.

Figure 1 shows a diagram of a device; figure 2 - stress diagrams at its characteristic points.

The device contains transmitting 1 and receiving 2 radiating cables located parallel to each other along the boundary, the intersection of which must be recorded. A pulse transmitter 3 is connected to the beginning of the transmitting cable 1. The receiving cable 2 is divided into several sections, the length of which is equal to the desired accuracy of determining the point of intersection. These segments are connected in series through the delay elements 4. The end of the receiving cable 2 is connected to the input of the receiver 5, the output of the receiver is connected via a range selector 6 to the input of the alarm supply unit 7, The end of the transmitting cable 1 through detector 8 and the clock generator 9 is connected to the second input of the selector range 6.

The device operates as follows.

For definiteness, the receiving cable 2 can be divided into five equal sections, between which four delay lines 4 are included. The section numbers are counted from the receiver.

Transmitter 3 generates radio pulses (Fig. 2a), which propagate through the transmission cable and are emitted by it into the surrounding space. Part of the energy of the radio pulses reaches the end of cable 1, is detected by the detector 8 and, through the clock generator 9, is fed to the second input of the range selector 6. These pulses are delayed relative to the pulses generated by the transmitter 3 during the signal propagation through cable 1 (Fig. 2b).

The radio pulses emitted by the transmitting cable 1 are received by the receiving cable 2. Since the distance between the cables is small compared to their length, it can be considered with a sufficient degree of accuracy that each point of the receiving cable receives only the signal emitted by the point of the transmitting cable closest to it. This assumption is confirmed both by calculation and experimentally.

Thus, the signal at the input of the receiver 5 is the sum of a large number of partial signals, each of which travels from the transmitter 3 through the transmitting cable 1 to some arbitrary point of it, is emitted at this point

it is received at the corresponding point on the receiving cable 2 and is transmitted through it to the receiver 5. Since the receiver 5 and the transmitter 3 are connected to the opposite ends of the cables 1 and 2, the sum of the distances traveled by each partial signal through the receiving and transmitting cables always constant and equal to the length of the boundary along which the cables are laid.

0 If cables 1 and 2 are identical, then all partial signals experience the same attenuation and make an equal contribution to the resulting signal at the input of receiver 5, At the same time, due to the presence of

5 delay lines 4, the signals received by each of the sections into which the receiving cable 2 is divided are delayed relative to the signals received by the previous section. As a result, the output of the receiver 5

0 each pulse generated by the transmitter 3 gives a group of pulses shifted relative to each other by the amount of delay in line 4. The first of these pulses practically coincides in time with the sync5 pulse at the output of the driver 9, and

their number is equal to the number of sites on which

cable 2 is separated. Voltage plots on

the output of the receiver 5 is shown in FIG. 2c.

The intersection of the boundary of the object leads to the fact that one of the partial signals as a result of interaction with the object changes. This causes a change in the amplitude of one of the pulses at the output of the receiver 5, namely, one whose number1

5 coincides with the number of the section where the intersection occurred. For example, when crossing a boundary in the second section, the amplitude of the second pulse will change. As noted above, all partial signals in this device have the same amplitude; consequently, the change in the amplitude of the pulse will be the same regardless of the place of crossing the boundary. The pulse of interest is highlighted by a range selector 6, the voltage plot at the output of which is shown in Fig. 2d, and enters the alarm supply unit 7.

Claims (1)

The claims 0 A device for registering a border crossing, comprising transmitting and receiving radiating cables located parallel to each other along the boundary, a pulse transmitter connected 5 to one end of the transmitting cable, the end of the receiving cable is connected to the receiver, which is connected via the range selector to the alarm supply unit, characterized in that, in order to increase the accuracy of detection, an input device We have a detector, a shaper, a sync pulse end of the transmitting cable through the posts and delay elements, and a receiving cable. the detector is connected to each other and is divided into sections that are connected to the clock between each other through delay elements, to the other-second input of the range selector. "-I ------ . s r ((r nr r --- ns njirL FIG. 2.