SU1291888A1 - Device for monitoring pulse signals - Google Patents

Abstract

The invention relates to electrical measurements and can be used in devices for automated monitoring and diagnostics of television equipment. The purpose of the invention is the expansion of functional capabilities by providing control levels of logical zero and logical unit and simplifying the device. The device contains a comparator 1, a trigger 2, a source 4 of the reference voltage. In order to achieve the above objectives, a control attenuator 3 and an integrator 5 are additionally introduced into it, for which an integrating KS circuit can be used. The controlled attenuator can be made on a resistive divider, the middle pin of which is the output of the controlled attenuator. 3 il. i cl fe /

Description

A device for monitoring pulsed signals can be used in devices for automated monitoring and diagnostics of television equipment.

The purpose of the invention is to expand the functionality by providing control of the levels of a logical zero and a logical unit, as well as simplifying the device.

FIG. 1 is an electrical block diagram of the device; in fig. 2 and 3 - stress diagrams.

A device for monitoring pulse signals contains a comparator 1, the first input of which is connected to the input of the device, and the output is connected to the counting input of trigger 2, the direct output of which is the first output of the device, and the inverse is connected to the control input of the attenuator 3 connected between the reference source voltage 4 and common bus, direct output trigger 2 is also connected to the input of the integrator 5, the output

which is the second output of the device, the output of the controlled attenuator 3 is connected to the second input of the comparator 1.

As an integrator 5, for example, an integrating RC circuit can be used, and a controlled attenuator 3 can be performed on a resistive divider, and a resistor is connected between the middle output of the divider, which is the output of the controlled-attenuator 3 and the control input.

The control device operates as follows.

In the absence of pulses at the input of the device, when the supply voltage is applied, trigger 2 is set to one of two states, and at its outputs, respectively, the voltage levels of a logical zero or one (Fig. 2a, b) (tp-t,). The voltage from the first output of the trigger 2 is fed to the first output of the device and to the input of the integrator 5. At the second output, a constant voltage of a logical zero or a logical unit is established (Fig. 2e, ()).

The voltage from the second output of the trigger 2 is fed to the input of the controlled attenuator 3 and, in accordance with the state of the trigger 2, changes the ratio of the voltages at the junction of the resistors.

five

0

five

When applying to the device input pulsed voltages, the level of the logical unit of which is not lower than the specified, and the level of the logical zero is not

exceeds the given value (fig. 2a, (t, -t2)), at the output of the comparator 1, with the arrival of each pulse, a voltage drop is formed, switching trigger 2 (fig. 26 and in, ()). The state of the second output of the trigger 2 connected to the control input of the attenuator 3 changes the resistance value of the attenuator connected to the source 4 of the reference voltage and, accordingly, the voltage on the second input of the comparator 1. This voltage differs from the original one corresponding to the previous state trigger 2 (Fig. 2d).

Thus, at the second input of the comparator 1, if there are input impulse voltages that satisfy the specified conditions, the following levels of reference voltage are alternately set: the voltage level corresponding to the lower acceptable value of the amplitude level of the input pulses (Fig. 2d, and,) , voltage level corresponding to the upper admissible value of the logical zero level of the input pulses (Fig. 2d, Uo).

In accordance with these support. Levels at the second input of the comparator 1 at its output periodically appear pulses only when the input pulses correspond to the specified conditions. The pulse voltage generated in this way at the output of trigger 2 has a duty cycle equal to two and a following frequency the frequency of the input pulses (Fig. 2b), is fed to the first output of the device and

input of the integrator 5. The presence of a pulse voltage at this output indicates that the input pulses correspond to given conditions.

0 The magnitude of the pulse voltage E at the output of the trigger 2 is determined by the selected type of trigger and the value of the supply voltage.

Integrator Output Voltage

55 5 is set with pulses equal to

,

0

0

where E is the supply voltage;

 - pulse duration; T - the period following. With the disappearance of pulses on the device, as well as their

states: - the logic zero level is exceeded (Fig. 3,); a decrease in the range of pulses below a given one (Fig. 3,); presence at the entrance

input faulty

logical zero levels -g-t,); presence at the entrance

Constant (Fig. 2, t constant level logical unit (Fig. 3, tg-tq), at the outputs of the comparator 1, trigger 2 and at the output of the device one of two discrete states is established: a constant level of logical unit or logical zero (Fig. 2,), depending on the state in which the trigger 2 is located and in which phase of the input signal the disturbance of the healthy state occurs. At the second output of the device, the voltage level corresponding to a logical zero or one is also set. Fig. 2 and 3 transition process are not shown, since T nT, where n -. number

pulses, t is the period of the following pulses at the output of trigger 2.

If the input pulses again meet the specified requirements :, the amplitude level of the logical unit is not lower than the specified one (Fig. 2) and the level

2918884

the amplitudes of the logical zero do not exceed a predetermined threshold (Fig. 2, t, -t), then at the outputs of flip-flop 2 (Q, Q) there appear pulses with a duty cycle equal to two and a following frequency — two times lower than the frequency of the input pulses (Fig. 3, tj-tg), and at the second output, a DC voltage equal to E / 2 is set, with predetermined permissible pulsations.

ten

Claims (1)

Invention Formula A device for monitoring pulse signals containing a counting trigger, a reference voltage source, a comparator, the first input of which is connected to the input of the device, and an output with a counting trigger input, characterized in that, in order to extend the functionality by providing control of logical zero levels unit and simplification of the device, a controlled attenuator and integrator are inserted into it, the second input of the comparator is connected to the output of the controlled attenuator connected between the output of the reference voltage and common wire, and the attenuator control input is connected to the second output of the trigger, while the first output of the trigger is connected to the first output of the device and the input of the integrator, the output of which is connected to the second output of the device. Uia a uo In ml hbi) (Q Turr. & % / x3 Ijiji t7 tg t9 tff Vsh2  I 0 tff i9 ii t8 is fe.J