SU1169200A1 - Device for blocking signals with varying lever for voice-frequency receiver - Google Patents

Description

The invention relates to telecommunications and can be used in receivers of tone signals to increase their protection from false positives under action 5

conversational currents ·.

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

In FIG. 1pr (a block diagram of the signal-blocking device with 10 levels with varying levels; Fig. 2 time ^ diagram of operation.

The device contains a full-wave rectifier 1, detector-attenuator 2, the first comparator 3, 15

detector 4, threshold pulse shaper 5, amplifier 6, sampling-storage unit 7, one-shot 8, second comparator 9, element OR 10.

The device works as follows 20

in a way.

The output signal (FIG. 2 <i) full-wave rectifier 1 is supplied simultaneously at ₂₅ neinvertiruyu- conductive input of comparator 3 and detektorattenyuator 2 representing the peak detector with a long time constant and a special reset circuit that carries out detection simultaneously with the attenuation ^ 0 .signala . The output signals of the detector-attenuator 2 and the full-wave rectifier 1 (respectively (% and ₂ , Fig. 2 m) are compared in magnitude in the comparator 3, the output signal. 35 which signal (, Fig 2-5),

representing a sequence of positive pulses, after detection with a small time constant (detector 4), 40 is fed to the input of the threshold pulse shaper. As follows from FIG. 2 a, and 5, the pulse repetition rate at the output of the comparator 3 (Fig. 25) does not change only in the case, 45

if the amplitude of each half-wave of the output signal of the full-wave rectifier 1 is greater than or equal to the previous one. In this case, the output signal (and ₄ , Fig. 2 £) of the detector 4 50

it does not have time to fall below the threshold of the threshold shaper of 5 pulses, the signal at the output of which in this case is equal to zero. ⁵⁵

If the amplitude of any half-wave of the output signal п of the full-wave rectifier 1 decreases as compared with the previous one by an amount greater than the attenuation value introduced by the detector-attenuator 2, then in the current half-period (Fig. 2 <5 ") a positive pulse at the output of the comparator 3 will not appear, resulting in the output signal of the detector 4 has time

to drop below the threshold of the trigger shaper 5 pulses, the output of which at the same time there will be a positive pulse discharging the detector-attenuator 2. ·

When the output level rises, the full-wave rectifier 1 output signal. and ₂ (.fig. 2 a) detector-attenuator 2 with some delay due to the presence of the amplifier 6, compensating for the attenuation introduced by the detector-attenuator 2, will exceed the voltage stored in block 7 of the sample-storage since the previous sample. As a result of this (Fig. 2 d), a positive voltage drop appears at the output of the comparator 9, which, passing through the element OR 10, triggers the one-shot 8. The positive pulse (AND ₉ , figure-2), appearing at the output of the one-shot 8, translates sampling block 7 — storage in the signal recording mode. Since the output signal of the detector-attenuator 2 is written to the sampling unit 7 through the amplifier 6, the comparator 9 quickly returns to its original state, but since the pulse duration at the output of the one-oscillator 8 is set comparable to the half-period of the input signal, the sampling-storage unit 7 has time to charge to the value corresponding to the peak value of the amplitude of the output signal of the full-wave rectifier 1 in the current half-period. After the end of the pulse at the output of the single-oscillator 8, the block 7 of the sampling-search The pass-through goes into the information storage mode, which exists only in those periods of time when the input level of the device is kept constant. In this case, the blocking impulses at the output of the element OR 10 do not appear.

Thus, as the input level rises, the positive

3

1169200

four

pulse appears at the output of the comparator 9 (, Fig. 2 9), and at

lowering the level - at the output of the threshold shaper 5 pulses (11y, fig. £ c). In both cases, positive impulses appear

in the output signal (and ₉ , Fig. 2 lg) of the element OR 10, and when starting the one-shot 8 update is allowed

5 information in block 7 generation-. storage (output signal and *

• FIG. 2d).

/ 'y 1 1 1 ί 7 R ~ • one —- <ί one ί ί -G ι. Ιι one

FIG. 2

Claims (2)

BLOCKING SIGNALS WITH A VARIABLE LEVEL FOR TONE SIGNAL RECEIVERS, Incubs, which are connected to the reset input of the detector-attenuator, which is connected by a pulse shaper, whose output is connected to the reset input of the detector, which is connected by inverting input of the first comparator, characterized in that, in order to increase the noise immunity, the series-connected the amplifier has a sample storage unit and a second comparator, as well as an OR element and a one-shot, the output of which is connected to the second input of the sample-hold block, and the one-shot input to the output of the OR element is the device output, and the output of the threshold pulse shaper is connected to the first input of the element OR, the second input of which is connected to the output of the second comparator, the non-inverting input of which is connected to the input of the amplifier and the output of the detector-attenuator. 5 and „„ 1169200 1 one 1169200 2