SU1187283A1 - Device for detecting contact noise - Google Patents

Description

The invention relates to radio engineering, serves to ensure electromagnetic compatibility (EMC) of radio electronic equipment (RES) and can be used on mobile 5 objects, mainly on ships.

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

FIG. 1 shows the block diagram of the device; in FIG. 2 - diagrams of voltages at the outputs of the device blocks.

A device for detecting contact interference consists of a control unit 1, a unit 2 for processing the output voltage of a radio receiver, and a signal analysis unit 3 for the number of analyzed hull areas. The control unit 1 consists of ^{1 20} rator racer 4 clock pulses, the first waiting multivibrator 5, the first differentiating circuit 6, the first limiter 7, the first inverter 8, the second waiting multi ²⁵ vibrator 9, the second differentiating circuit 10, the element OR 11, a trigger 12, the second limiter 13, the second inverter 14, and the indicator 15. 30

The unit 2 for processing the output voltage of the radio receiver consists of the detector 16, the primary limiter 17, the element OR 18, the driver 19 pulses, the inverter 20, 35

the second limiter 21.

Each signal analysis unit 3 consists of a vibrator 22, a second limiter 23, a second pulse shaper 24, an element 40 OR 25, a first element AND 26, a first counter 27, an inverter 28, the first limiter 29, a first driver 30 pulse, a second element And 31 , the second counter 32, the decoder 33.

The device works as follows.

The generator 4 clock pulses generates a sequence of short pulses (Fig. 2c), the period between which is equal to the update time of the indicator 15, The pulses from the generator output 4 clock pulses are fed to the input "Reset" of the first and second counters 27 and 32, zeroing them. The first one is a multivibrator 5 — it starts up with short pulses of a generator of 4 clock pulses and outputs pulses (FIG. 2 K), the duration of which is equal to the delay of the beginning of the analysis time of the output and reference voltages relative to the moment the circuit is brought to its initial state (zeroing).

Using a chain connected in series to the first differentiating circuit 6, the first limiter 7 and the first inverter 8, the output diagrams of which are shown in FIG. 2 £>, Ί, - receive 'triggering positive pulses of the second standby multivibrator 9, the output pulses of which (Fig. 2 c) determine the time of analysis of the reference voltages and the output voltage of the radio receiver. The beginning of the analysis time is determined by the leading edge, the end by the falling edge of the pulse, the shortened pulses corresponding to the leading and falling edges are half 1187283

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are given at the output of the second differentiating circuit 10 (Fig. 2 ^ ς).

The positive impulse corresponding to the leading edge of the analysis impulse comes through the element ^ 5

OR 11 to the input of the trigger 12, setting it in position (Fig. 2 K), in which the first and second elements AND 26 and 31 open the access of the input pulses to the input K, respectively

the first and second counters 27 and 32.

The output voltage of the radio receiver at the second intermediate frequency (Fig. 2 Λ) is · ρ

the sum of the useful signal and contact interference. Contact disturbance is the voltage of an interfering transmitter modulated in amplitude and phase by voltage; corresponding to the hull vibration of the vessel. Vibration causes the opening of a permanently closed contact, periodic with a frequency of vibration, or the closing of a constantly open contact. When closing (or opening) a contact, the resistance of the upper-deck structure radiating a secondary electromagnetic field changes dramatically. This is resistance. it abruptly decreases (or increases), which leads to current drops, and, consequently, voltage disturbances acting on the radio receiver.

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The proposed device provides a selection of these differences in. • voltage interference coming into the processing unit 2. To this end, the output voltage of the radio receiver 40 (Fig. 2a) is detected by the detector 16 (amplitude). The envelope of the analyzed voltage (Fig. 2m) is fed simultaneously to the first limiter 17 from the bottom and the inverter 20. 45

If the contact disturbance is a voltage surge (voltage increase), then the output of the first limiter 17 will generate pulses corresponding to these '50

throws (Fig. 2 N), which pass through the element OR 18 and start the imaging unit 19 pulses, issuing output pulses of constant duration (Fig. 20). As a pulse shaper, a stand-by multivibrator can be used.

If the contact disturbance represents voltage dips, then the output of the first limiter 17 will be zero voltage, and the pulses corresponding to the dips will be generated using the inverter 20, the second limiter 21 from the bottom, and the former 19 as described above. Thus, at the output of block 2, there is a sequence of imps that periodically repeat with the frequency of the vibration of a constant contact and at the instants of time when the amplitude of vibrations reaches its maximum value. This sequence of pulses is supplied to thirds; the input of the first element And 26.

In block 3, the analysis of the vib signals: a transducer 22 placed in a specific area of the ship's decks gives out the stress of the vibration of the hull (Fig. 2 and). Two parallel chains consisting of successively connected second limiter 23 ch; the pulse and the second pulse shaper 24, the inverter 28, the first stop 29 from the bottom and the first φι worldviewer 30 pulses, give t sequences of pulses, periodically following each with a vibration frequency of the analyzed hull area and corresponding to the positive (Fig. 2p) and denied; telny (Fig. 2c) vibration amplitudes. At the output of the OR 25 element, a sequence of pulses is formed (Fig. 2m), the repetition frequency of which is 2 times more often the vibration, but it is during these; Impulses are possible differences (choices or dips) in the output voltage of the radio receiver, if the neg is affected by contact interference.

Thus formed pulse sequence is fed to the input of the first element AND 26, the output of which (Fig. 2 q) will only show coincidence impulses from the pulse sequences fed to the first and third inputs, and only during the analysis time determined by pulse at the output of the second standby multivibrator 9. And the pulses that passed the first element And 26 are counted by the first counter: com 27 during the analysis time.

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The number of differences in the output voltage of the radio receiver, which coincided in time with the maximum amplitude of vibrations, should be equal to the product of the vibration frequency and the analysis time, which is recorded by the counter 27.

Consecutive connected the second element And 31 and the second counter 32 is used to count the number of pulses generated by the first driver 30 pulses and the corresponding vibration frequency passed through the second element And 31 during the analysis. If there is a contact disturbance in the output voltage of the radio receiver, caused by the vibration of the ship's hull in a certain area, then the readings of the first and second counters 27 and 32 of the corresponding signal analysis unit 3 will be equal at the same time points.

At the end of the analysis time (the falling edge of the output pulse of the second standby multivibrator 9 _? Fig. 2 ^ ·), a positive pulse appears at the output of the second inverter 14 (Fig. 2 and), which through the element OR 11. pulses on the first and second counters 27 and 32 pulses. The same impulse simultaneously arrives at the control input of the indicator 15, resetting all its outputs, as well as at the “Read” inputs of the first and second counters 27 and 32. The counter bits output signals are sent to the decoder 33, and

₅ when these values are equal, a signal pulse appears at the output of the decoder 33, which is fed to the input of the indicator 15, corresponding to the area of the ship's hull

10 in which the vibration transducer 22 is placed, functionally associated with this decoder 33.

Indicator 15 is a set of ordinary triggers, in the load of 15 one of the arms of each of which the warning light is on. The control input of the indicator 15 is connected to the inputs "Reset" of all triggers, and the signal at this input

20 triggers are set to a position in which the indicator lights are off. The output of each decoder 33 is connected to the input of the corresponding trigger, and when

25 of the signal at the output of the decoder 33, the corresponding trigger of the indicator 15 switches to another steady state, in which the potential in the arm with the signal lamp.

30 turns high and the light comes on.

Thus, the appearance of the pulse on one of the signal inputs of the indicator 15 identifies Nali ₃₅ Chie contact noise in the output

receiver voltages and the ship's hull area, where the structure is located with non-constant contact.

FIG!

1187283.

Claims (1)

DEVICE FOR DETECTION CONTACT DIFFERENT, containing a control unit consisting of a clock pulse generator, a first multivibrator standby, a trigger, an indicator and connected in series to the first differentiating circuit, a first limiter, a first inverter and a second multivibrator standby, a signal analysis unit consisting of the first element And connected in series, the first the input of which is connected to the trigger output of the control unit, the first counter and a decoder, the output of which is connected to the signal input of the indicator, characterized in that, in order to improve the accuracy of contact noise detection, a processing unit for the output voltage of the radio receiver and additional identical signal analysis units are introduced, and the second terminator connected in series is inserted into the control unit , the second inverter and the OR element, the output of which is connected to the trigger input, and the other input is connected to the output of the second differentiating circuit, whose input connected to the output of the second standby multivibrator, the output of the clock generator through the first standby multivibrator is connected to the input of the first differentiating circuit, and the output of the second inverter is connected to the control input in; kator; The processing unit for the output voltage of the radio receiver consists of a series-connected detector, a first limiter, an OR element and a pulse former <>, as well as a series-connected inverter and a second limiter connected between the detector output and the second input element, OR, and serially connected in each of the signal analysis blocks. A vibration converter, an inverter, a first limiter, a first pulse shaper, a second AND element and a second counter, the output of which is connected to the second inputs of the decoder, as well as sequentially connected to the second the limiter whose input is connected to the output of the vibration converter, the second pulse generator and the OR element, the output of which is connected to the second input of the first element I, and the second and the input connected to the output of the first 4 pulse leveling device, and in xc PFN unit arr Botko radio output voltage is connected to the third rows of first elements SEC And yavlyayuschig · Xia first inputs of each of blokog analyzing signals input "reset" cerned counter coupled to an input "reset" schetchikg first and the second input unit 00 eo > 1187283 signal analysis, the input "Read" the second counter is connected to. the input "Read" of the first counter is the third input of the signal analysis unit, the second input of the second element I is connected to the first input of the first element AND, and is the fourth input of the signal analysis unit ,. moreover, the outputs of the generator clock pulses of the trigger and the second inverter of the control unit are connected respectively to the second, fourth and third inputs of each of the additional signal analysis blocks, the outputs of the decoders of which are connected to the additional signal inputs of the indicator.