SU811497A1 - Selector of pulses by duration - Google Patents

Description

The second input is through the first element NOT to the input bus and the first input of the second element And, the pulse generator, the output of which is connected to the first input of the third element And, the element. OR and the second element is NOT, the inputs of the element OR are connected to the outputs of the first and second elements AND, and the output to the second input of the third element AND directly and through the second element NOT to the reset input of the pulse counter, the counting input of which is connected to the output of the third element AND the second trigger output is connected to the second input of the second element I.

The drawing shows an electrical functional circuit diagram of the device.

The selector contains the element NOT 1, the elements AND 2-4, the element OR 5, the generator 6 pulses, the element 7, the counter 8 pulses and the trigger 9. The device input bus is connected to one of the inputs of the element 3 and directly and to one of the inputs of the element AND 2 through the element NOT 1. The outputs of the elements AND 2, 3 are connected to the inputs of the element OR 5, the output of which is connected to one of the inputs of the element AND 4 directly and through the element NOT 7 to the reset input of the counter 8, to the counting input of which through the elements AND 4 generator 6 is connected. The output of counter 8 is connected to the counting input trigger 9, the unit output of which is the output of the device and, moreover, is connected to the second input of the AND 2 element, and the zero output of the trigger is connected to the second input of the AND 3 element.

The device works as follows.

The input rectangular impulse through the AND 3 element, unblocked by the second input with a single signal from the zero output of the trigger 9, and the OR 5 element enters the input of the AND 4 element, which is filled with counting pulses of the generator 6, the number of which is proportional to the signal duration. These pulses from the output of the element 4 are fed to the input of the counter 8. The conversion factor L of the counter 8 is proportional to the selection threshold Tc. If the duration of the input signal Gx satisfies the condition, the pulse at the output of counter 8 is absent. With the end of the input pulse, the zero signal from the output of the element OR 5 stops the flow of pulses from the generator 6 to the input of the counter 8 and zeroes the latter through the element HE 7.

If the duration of the input signal Tx satisfies the condition, then after the arrival of N counting pulses at the input of the counter 8, a pulse appears at the output of the latter, which sets the trigger 9 to the single position. From this point in time, a pulse begins to be generated at the device output and the filling of the input pulse by the counting pulses of generator 6 stops, since element 3 is blocked by the second input by a signal from the zero output of trigger 9, and to the first input of the element 2 unblocked by the second input from the single output of the trigger 9, a zero signal comes from the output of the element NOT 1. Thus, at the output

element OR 5 there is a zero signal, which blocks the passage of pulses at the output of the element AND 4 and sets to zero the counter 8 through the element NOT 7. When the pulse at the device input

is interrupted, i.e. a pause appears, at the output of the element NO 1 a pulse equal in duration to the pause appears. This pulse through the element AND 2 and the element OR 5 is fed to the input of the element AND 4, with which it is converted into pulses, the number of which is proportional to the length of the pause. These pulses are fed to the input of the counter 8. If the duration of the pause tp satisfies the condition, the pulse

the output of the counter 8 is absent, and the state of the trigger 9 does not change, i.e. the pause is perceived by the device as an interference superimposed on the desired signal. If the duration of the pause, then after

A counting pulses will be input to the counter, and a pulse will appear at the output of the latter, which will transfer trigger 9 to the initial (zero) state. This ends the appearance of a noise-free impulse device at the output, the duration of which is equal to the duration of the input signal.

Simultaneously, a change in the state of trigger 9 causes the termination of work

the counter 8 and setting it to the zero state by a signal from the output of the element OR 5 through the element NOT 7. Consequently, after the formation of the pulse at the output of the device ends, the counter 8 and the trigger 9 are in the zero state, and the device is ready to receive the next pulse.

Thus, the device provides, in the presence of interference, a selection of pulses, the duration of which exceeds a predetermined

threshold value and can be arbitrarily large. In this case, a pulse is generated at the device output, the duration of which is equal to the input duration, if the maximum duration of the interference,

causing the appearance of a false pulse or suppression of the useful signal, as well as the minimum time interval between the moments of the appearance of interference, is limited by the value of the selection threshold.

Claims (2)

1. USSR Author's Certificate No. 558394, cl. H 03 K 5/18, 1976. 2. USSR author's certificate number 630739, cl. H 03 K 5/18, 1977 (prototype).