SU1311005A1 - Pulse repetition frequency discriminator - Google Patents

Abstract

The invention relates to a pulse technique and can be used in automation and computing devices. The aim of the invention is to increase the noise immunity. To achieve this goal, the RS-flip-flop 3 and shaper 1 are additionally entered into the pulse selector. In addition, the device contains an input bus 2, one-shot 4, 5 and 8. AND-NE element 6, delay element 7, AND 9 element, output bus 10 The selector reproduces in the transmission zone the input pulses without distortion in shape and phase. It has a hysteresis characteristic, which allows the use of a selector in automated tracking frequency control systems, in which minor frequency deviations caused by interference, should not lead to false actuators. 3 il. ifi (/) 7tf fig1

Description

1 13

The invention relates to a pulse technique and can be used in automatics and computing devices.

The aim of the invention is to improve the noise immunity.

Figure 1 shows the functional logic diagram of the device; figure 2 - output characteristic; on fig.Z - timing charts of the device.

The pulse selector with respect to the following frequency contains the shaper I whose input is connected to the input bus 2, the first output to the clock input of the trigger 3, and the second output to the inputs of the first 4 and second 5 single-oscillators. The inverse output of the single-vibrator 4 is connected to the first input of the NAND 6 element, the second input of which is connected to the direct output of the one-vibrator 5, and the output to the R-BXO- house of the trigger 3 and through the delay element 7 is connected to the input of the third single-vibrator 8, the direct output of which is connected to the S-input of the trigger 3. The output of the trigger 3 is connected to the second input of the element AND 9, the first input of which is connected to the input bus 2, and the output to the output bus 10.

The pulse selector works as follows.

The input pulses go through bus 2 to the input of shaper 1 (Fig. 3, Pa) and the first input of element 9. 9. At the first and second outputs of shaper 1, pulses of duration €; grayness appear, twice the frequency shifted by each relative to each other (fig. Za. Pro, and 2. 1 2a, respectively). The pulses from the second output of the imager 1 cut off the one-shot 4 and 5 at the cut-off. On the inverse output of the single-vibrator 4 and the direct output of the one-shot 5, reference pulses T and t are formed, the duration of which determines the bandwidth of the selector (Fig.3.14a and 3.15a respectively, from the inverse output of the one-shot 4 and the direct output of the one-shot 5, the reference pulses arrive at the element AND-HE 6, where a pulse of duration equal to the difference of the durations of the reference pulses is formed (FIG. 3.16). The differential pulses from the output of the element AND-HE 6 arrive to the R-input of the synchronous RS-flip-flop 3, the clock input of which is supplied by it52

pulses from the first shaper output 1.

In order to prevent the unstable operation of the selector, a symmetric shortening of the difference pulse by the value of Г7 / Трg (figure 3.17a) is carried out at the boundaries of the passband (figure 3.17a), which is carried out using a single vibrator 8 and a delay element 7

(L is the delay time of the signals in element 7). 11 puls: the cusps from the output of the one-shot 8 (Fig. 3.17a) are fed to the S input of the synchronous RS flip-flop 3, which is set to one state,

if the clock pulse coincides with pulse 1 (FIG. 3.18a). If the frequency of the input pulses is below the transmission band, then trigger 3 will be in the zero state and the pulses

on the output bus 10 are missing (fig.Z.G9a).

When reducing the period of input pulses (T c,), trigger 3 will be set to a single position, provided

 In this case, the logical voltage (figure 3.186) is applied to

the second input element And 9, allowing the passage of input pulses to the output bus 10 (Fig.3.196), while the output pulses in exactly the same input.

With a further decrease in the period of input pulses, trigger 3 is transferred to the zero state, if the clock pulse goes beyond the limits of the joy pulse (figure 3.18b),

those. if a

-0 I

In this case, the logical voltage O is applied to the element 9 and the output pulses are absent (Fig. 3.19c).

At a high frequency of input pulses, first the one-shot 5 begins to generate a constant voltage of logic I, and then the single-vibrator 4 begins to generate a constant voltage of logic O, trigger 3 continues to be in the zero state and the output

pulses are absent.

With an increase in the period of input pulses, trigger 3 is transferred to one state, if,

, At the same time, on bus 10, pulses appear, in frequency, duration and phase coinciding with the input ones. With a further increase in the period of the output pulses, the trigger 3 is transferred to the zero state, if Tg y / i. Thus, the output characteristic of the selector is represented as a hysteresis loop (Fig 2), where a high voltage level corresponds to the mode of the pulse passing to the output Tina 1 O.

The considered pulse selector in terms of the repetition frequency reproduces in the transmission band the input pulses without distortion in shape and phase and possesses a hysteresis characteristic that allows this pulse selector to be used in automated tracking frequency systems, where minor frequency deviations caused by interference, should not lead to false actuators.

Ti Tj- t-Tffn. G, GG-G. FIG. g

4 Formula of invention

The pulse selector in terms of the following frequency, contains the first one-channel vibrator, the input of which is connected to the input of the second one-vibrator, and the inverse output with the first input of the NAND element, the second input of which is connected to the direct output of the second one-vibrator, the third personalizer, the holder element and the And, the output of which is connected to the output mud, characterized in that, in order to increase the noise immunity, a trigger and a driver are inputted into it, the input of which is connected to the input bus and the first input of the And element, the second input of which is connected to direct output of the trigger, the S-input of which is connected to the direct output of the third one-shot, R-input is connected to the output of the NAND element and the input of the delay element, the output of which is connected to the input of the third one-shot, and the first output of the driver is connected to the clock input of the trigger, and the second output - with the input of the first one-shot.

 compiler A. Sazonov

Editor M, Bandura Tehred I. PopoEzhch

Order 1901/54 Circulation 902 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5

Production of a printing company, .Uzhgorod, yji. Prszektna, 4

Kresek t) r G. R e et n ik

Claims (1)

Claim A pulse picker according to the repetition rate, containing the first one-shot, the input of which is connected to the input of the second one-shot, and the inverse output - with the first input of the AND-NOT element, the second input of which is connected to the direct output of the second one-shot, the third one-shot, delay element * and the element And, the output of which is connected to the output bus, characterized in that, in order to increase the noise immunity, a trigger and driver are introduced into it, the input of which is connected to the input bus and the first input of the And element, the second input of which is connected to direct output of the trigger, the S-input of which is connected to the direct output of the third one-shot, R-input is connected to the output of the AND element and the input of the delay element, the output of which is connected to the input of the third one-shot, and the first output of the driver is connected to the clock input of the trigger, and the second output - with the input of the first one-shot. Fig 2