SU1663748A1 - Frequency discriminator - Google Patents

Abstract

The invention relates to electrical measurements and can be used to monitor frequency. The purpose of the invention is to simplify the discriminator by eliminating the memory block. The goal is achieved by serially connecting the first and second single vibrators 1 and 2 with restarting and connecting the direct and inverse outputs of the first and second single vibrators 1 and 2, respectively, with the inputs of the coincidence element 3. 2 Il.

Description

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The invention relates to electrical measurements and can be used to monitor frequency.

The purpose of the invention is to simplify the device by eliminating the memory block,

Figure 1 shows the structural electrical circuit of the frequency discriminator; FIG. 2 shows timing diagrams explaining its principle of operation.

The frequency discriminator contains the first 1 and second 2 one-shot with the restart and element 3 matches.

The frequency discriminator works as follows.

The principle of the frequency discriminator is based on comparing the input signal period (ti and ta in fig. 2a) with the pulse duration of the first one-vibrator 1 (tM in fig. 2b), and the pulse duration of the first one-vibrator 1 t. Determines the response threshold of the frequency discriminator . The second one-shot 2 is triggered by the output pulse of the first one-shot 1 with a restart, the output pulse of the second one-shot 2 must be longer than the maximum period of the input signal. A positive differential pulse arriving at the input of the frequency discriminator (Fig 2a) triggers the first single-shot 1 with a restart, generating an output pulse (Fig. 2b), the action time of which adjusts the threshold of the frequency discriminator in advance. If the period of the input signal is longer than the duration of the output pulse of the first one-oscillator 1 (ti, ti), then due to the positive differences of the pulse from the output of the first one-oscillator 1 the second one-oscillator 2 will always be in a neglected state, since its output pulse duration is longer than maximum value of the period of the input signal. As a result, the inverse output of the second one-shot and the second input

element 3 matches (performed, for example, on the element I) there will be a low level (figv), respectively, and at the output of the element 3 matches

a low level will be present (Fig. 2d), indicating that the frequency of the input signal is below the threshold of the frequency discriminator.

If the period of the input signal is equal to or less than the duration of the output pulse of the first one-shot, then the output of the first one-shot 1 will have a high level (Figure 26) (the first one-shot 1 will be in

running state), the second one-shot 2 will not run anymore (since there will be no drops at the output of the first one-shot), therefore after the expiration of the output pulse time of the second one-shot 2 the high level will be present at its inverse output. Since both inputs of the coincidence element 3 receive signals with a high level, a high level will also be present at its output (Fig. 2d), indicating that the frequency of the input signal is equal to or higher than the threshold of the frequency discriminator.

Claims (1)

Invention Formula A frequency discriminator containing the first one-shot with a restart, the input of which is the input of the frequency discriminator, as well as the second restart one-shot and match element whose output is the output of a frequency discriminator, characterized in that, in order to simplify the frequency discriminator by excluding a memory unit, the output of the first restart one-shot is connected to the first input of the match element and the second one-shot with the repeated a trigger whose inverse output is connected to the second input of the matching element. tu "G FIG. 2 j, i