SU573869A1 - Frequency discriminator - Google Patents

Description

The invention relates to a pulse technique and can be used in an automatics, emery, body. and digital technology and s zi. A frequency discriminator is known that contains a series-connected differentiating input device consisting of two NOT gates, a half-adder and two capacitances, a single-stagger pulse shaper made by an awning multivibrator with noBToptoiM starting, a coincidence circuit, and an output device. A disadvantage of this device is the need to perform a single-stable pulse generator with a restart, which complicates the discriminator circuit. The closest to the invention in terms of its technical nature is the frequency discriminator, which includes an input trigger with a counting input, a single-pulse pulse shaper, and an output trigger with a counting input. The shaper consists of two serially connected waiting multivibrators, one of which is made according to the scheme with a restart. The disadvantage of this discriminator is the instability of its operation. To eliminate this drawback, the proposed frequency discriminator, containing an input trigger, whose input is connected to an input source, and the output is connected to the input of a fixed-frequency pulse shaper, and an output trigger of the ZK-type, has two logical elements AND and a logical element OR. The inputs of one logical element I are connected to the second output of the input trigger on one of the outputs of the single-stable pulse driver, the inputs of the second logic element I are connected to the first output of the input trigger and the second output of the single-stable pulse generator, one input of the logical element OR is connected to the output of the first logic element. And the second input - with the first output of the trigger input, and the outputs

logic elements AND and OR are connected to the corresponding inputs of the output trigger D of the K-type.

The drawing shows a structural electrical circuit of the proposed frequency discriminator.

Dionriminator contains an input trigger 1 "one-stable pulse shaper 2 logic elements AND 3, 4, logic element OR 5, output trigger -6. An input pulse signal is fed to the input 7 of the discriminator, the output signals of the LN1 are SINKED from the outputs 8, 9.

The work of the discriminator is in the following.

The pulse signal is fed to the input 7 of the frequency discriminator. In this case, trigger 1 is triggered by the front edge of the input pulses of positive polarity. The direct output signal of the trigger 1, which is fed to the inputs of the imaging unit 2 and logic elements 4 and 5, the frontal frotom of positive polarity pulses starts the shaping device 2, the forward and inverse output signals of which correspond to Cgeek) and to the inputs of logic elements And 3, 4, On the other input of the logic element And 3 receives the inverse output signal of the trigger 1. Corresponding signals, having passed through the logic elements AND 3, 4 and the element OR 5, are transformed with into three definite sequences of signals.

The output signal of the logic element 4 is generated to the cutoff frequency of the operation of the discriminator. The pulses i of the positive utility of this signal come to the input of the reset K of the trigger 6. The pulses of the positive polarity of the signal supplied to the start input 3 of the trigger 6 are formed as a result of the coincidence of the signals from the outputs of the trigger 1 and the former 2. The pulses of the positive half received by the counting input of the trigger 6 are formed as a result of

the additions of the signals in the element OR 5, These pulses are the clock pulses of the trigger 6.

The duration of the output pulses of positive polarity of the signal 3 is set by the driver 2 and determines the limiting response frequency of the discriminator, at which the output of the driver 2 has a duty cycle equal to two.

If the repetition frequency of the input pulses is less than a predetermined cutoff frequency of the discriminator, then the counting reset input of the trigger 6 from the output of logic elements 4 and 6 receives the coincident pulses of the positive field of the phpx, and at the output 9 a logical zero is set. At the same time, there is no signal at the input of trigger O of trigger 6.

If the repetition frequency of the input pulses is equal to or greater than the predetermined cutoff frequency of the discriminator, the trigger input and the counting input of the trigger 6 receive positive polarity output pulses from logic elements 3 and 5. At the same time, the signal at the reset input of the trigger 6 is absent and output 8 sets logical unit.

With a further increase in the repetition frequency of the input pulses at the output 8 of the discriminator, the logical unit is retained. As a result of the miscalculation of shaper 2, pulses of positive UTILITY from the output of the I 4 element begin to arrive again at the reset input of trigger 6.

Claims (1)

Invention Formula Frequency discriminator, containing an input Krigger, whose input is connected to an input source, and an output connected to the input of a single-stable pulse generator, and an output trigger About a K-type, characterized in that, in order to increase the stability of the discriminator, two AND logical elements and an OR element, inputs of one AND logic element are connected to the second output of the trigger input and one of the outputs of a single-stable pulse generator, and inputs the second logic element And connected to the first output of the input trigger and the second output of the single-stable pulse shaper, one input of the logical element OR is connected to the output of the first logical element AND, the second input - with the first output of the input trigger and the outputs of the logical elements AND and OR are connected to the corresponding inputs of the output trigger of the K-type.