SU1411951A1 - Device for selecting the first and last pulses in a series - Google Patents

Abstract

The invention relates to a pulse technique and can be used in pulse devices with a reduced level of interference, and also in start-stop type devices. The aim of the invention is to improve the accuracy of the selection of the first pulse, which is achieved by introducing a second delay element and the proposed functional communication scheme. The drawing shows the D-flip-flop 1, the one-shot 2, the input bus 3, the output tires 4 and 5, the initial setting bus 6, the elements 7 and 8, the delay elements 9 and 10. The device prevents false triggering, i.e. the appearance of unnecessary signals on the output bus 4, although a pulse is generated on the output bus 6, as a result of the arrival of a disturbance pulse at the trigger switching level of 1. 2 Il. &

Description

R

one

(L

about sd

I.I

Fig, 1

The invention relates to a pulse technique and can be used in a pulse device with a reduced noise level and start-stop type devices.

The purpose of the invention is to improve the accuracy of the first pulse in the series.

Fig. 1 shows the electrical level at the output of the element as a functional diagram of the device; in fig. 2 - time diagrams that show his work.

A device for extracting the first and last pulses in a series contains a D-flip-flop 1, a single vibrator 2, an input bus 3, output buses 4 and 5, an initial installation bus 6, the first 7 and second 8 elements, and the first 9 and second 10 elements. delay, the bus 20 3 connected to the first input of the first element And 7, S and D inputs of the trigger 1 and through the one-shot 2nd C input trigger 1, the R input of which is connected to the bus 6 of the initial installation, direct 25 output - with the second input element And 7 and through the first element 9 delay - with the third input element And 7, and the inverse output with the first The second input element And through delay element 1030 - with the second input element And 8, the output of which is connected to the output bus 5, the output of the element And 7 connected to the output bus 4. The parameters of the one-oscillator 2 are chosen so that the end of the pulse its output was at the time of the presence of a pulse in the series, and it was triggered by the falling edge of the input pulse. Then

35

(fig. 2d) is formed only when the first pulse of the series drops at its inputs, the high level at the direct output of the trigger and the high level at the output of delay element 9. The signal strength of the output element And 7 depends on the length of the delay element of the delay and the duration of the first and pulse. After the completion of the pulse formation at the output of the element And 7, the last is closed at the input by a low level from the output of the element 9 delay, therefore all subsequent pulses from at the end of the element And 7 do not form

Pulses generated on a single vibrator 2, trigger state

2 do not change. The last impulse of the series, with the falling edge, forms the next impulse with duration f (Fig. 26). The back front of this (fig. 2g) impulse arrives at the C input of the trigger 1 and sets a low level to its forward output, that is, The level of the signal on the DB de. A high level signal formed on the inverse output of flip-flop 1 forms a pulse on bus 5 (Fig. 2e) corresponding to the end of a series.

 AND

7 t

P

50

where tg is the duration of a pulse generated by a single vibrator; tp - the duration of the pause of pulses

series

 About the pulse duration of the series,

A device for separating the first and last pulses in a series operates as follows.

In the initial state, the pulses are not fed to the input bus 3 of the device. The device is set to the initial state via the initial installation bus 6, i.e. at the direct output of the trigger 1 - low, and at its inverse output - high. On output buses 4 and 5 - low signals

55

19512

level The first impulse of the series (Fig. 2a), which arrived on the bus 3 of the device, sets a high level to the forward output of the trigger 1 high level (Fig, 2c). The high signal from the direct output of the trigger 1 enters the input element And 7 and the input element 9 delays. Signal

0 low level at the output of the element

15 20 25 30 35

40

on you- and 7

(FIG. 2d) is formed only when the first pulse of the series coincides in time at its inputs, a high level at the direct output of flip-flop 1 and a high level at the output of delay element 9. The signal power at the output of the element And 7 depends on the magnitude of the delay time of the delay element and the duration of the first pulse. After the formation of the pulse at the output of the element And 7 is completed, the latter closes on the input with a low level from the output of the delay element 9, therefore all subsequent pulses of the series at the end of the element And 7 are not formed.

The pulses formed at the output of the one-shot 2, the state of the trigger

2 do not change. The last impulse of the series, with a falling front, forms at the output of the one-vibrator 2 a regular impulse of duration f (Fig 26). The falling edge of this (fig 2g) impulse arrives at the C input of the trigger 1 and sets a low level at its forward output, t, e. state corresponding to the level of the signal on the D-BXO. The high level signal formed at the inverse output of trigger 1 generates a pulse on bus 5 (Fig. 2e) corresponding to the end of the series. In the case of admission to the bus

3 clutter duration

50

s

 t

about f

where t

Oi

er

trigger 1

pow -3, p

the delay time of the appearance of the signal at the output of the trigger 1 relative to the arrival of the signal at its S input, at the forward output, not earlier than

five

a high level signal will be generated. At this time, the signal of interference from the input bus 3 at the other input of the element And 7 is already absent, which eliminates the false response of the device, t, e. the appearance of unnecessary signals on the output bus 4 of the device, although the output bus 5 forms

impulse, as a result of the arrival of a disturbance pulse at the trigger switching level 1.

Claims (1)

Invention Formula A device for extracting the first and last pulses in series, containing an input bus connected to the single-shot input, a first delay element whose output is connected to the first input of the first And element whose output is connected to the first output bus and the second input to the forward trigger output , The R-input of which is connected to the initial bus ff iff ") s installation, and the inverse output with the first input of the second element I, which is connected to the second output bus, characterized in that, in order to improve the accuracy of the selection of the first pulse, a second delay element is introduced into it, the output of which is connected to the second input of the second element 1ta And and the input with the inverse trigger output, the direct output of which is connected to the input of the first delay element, the C input to the one-shot output, and the S input to its same D-input, to the input of the one-shot and the third input of the first element And . AND AND f / №ft P fa rm P yy