SU417897A1 - - Google Patents

Description

The invention relates to a pulse technique.

By bus. St. No. 363195 — known is the pulse frequency discriminator, which contains a pulse frequency threshold element, a switch-on time delay element, a recording trigger, a valve element, and a shut-down speed element.

However, such a searchrimer has a low noise immunity.

The purpose of the invention is to increase noise immunity with significant fluctuations of the pulse frequency.

This is achieved by introducing into the proposed discriminator an additional time delay element, the input of which is connected to the output of the frequency-pulse threshold element, and the output is connected to the control input of the valve element.

The drawing shows a schematic diagram of the discriminator.

The frequency discriminator contains the frequency-pulse threshold element 1, the time-out element 2 for shutdown, the recording trigger 3, the additional time-element 4, the valve element 5, the time-out element 6 for the time-out and the voltage regulator 7.

The frequency-pulse threshold element includes tunnel diodes 8, 9, transistors 10, 11, resistors 12, 13, 14 and capacitors 15, 16.

An additional time delay element contains a transistor 17, resistors 18, 19, and a capacitor 20. The gate has a transistor 21 and a capacitor 22. The turn-on time element consists of transistors 23-26, tunnel diode 27, capacitor 28, and resistors 29-33. The element of the time delay for switching off includes transistors 34, 35, 36, tunnel diodes 37, 38, capacitor 39 and resistors 40, 41, 42. The registering trigger consists of transistors 43, 44 and resistors 45-50. The voltage regulator contains a zener diode 51 and a resistor 52. The discriminator operates as follows.

In the initial state, in the absence of pulses at the input of the discriminator, the positive potential from tunnel diode 9 opens transistors 17, 23. At the same time, the disconnect signal comes from the output of the time delay element to the disconnect to the zero input of the recording trigger. The negative potential from the output of the time delay element 4 opens the transistor 21, which corresponds to the closed state of the valve element. At the output of the element of time delay for inclusion in the initial state

no start signal.

When a single negative impulse arrives at the input of the threshold element 1, a threshold impulse is formed. The duration of the threshold pulse is equal to the period of the threshold frequency and is determined by the circuit parameters. During the period of formation of the threshold pulse, the voltage on the tunnel diode 9 is absent and, therefore, there is no voltage at the inputs of the time delay switching element and the time delay element. One, the turn-on signal does not appear at the output of the time delay element pa because the element is tuned to the time, which is our time, its several threshold frequency periods. The transistor 17 is closed and the capacitor 20 is discharged through the resistor 19 and the base transition of the transistor 21.

After the capacitor 20 is discharged, the transistor 21 closes and opens the valve element. The magnitude of the delay in opening the valve element must not exceed the duration of the pulses arriving on the discriminator input, since single pulses must not pass through the valve element to the input of the time-delay element for switching off. Due to the fact that the duration of the pulses arriving at the input of the threshold element 1 is significantly less than the period of the threshold frequency, the dwell time of the element 4 is also significantly less than the period of the threshold frequency. When the formation of the threshold pulse is completed, a voltage appears on the tunnel bottom 9 and the valve element closes.

If the frequency of the pulses at the input of the discriminator becomes greater than the threshold frequency, the threshold pulses merge at the output of the threshold element 1, and the voltage on the tunnel diode 9 does not appear. Through the open valve element, negative pulses enter the input of the time-delay element for switching off, and at the output of this element the switch-off signal disappears. At the same time, a turn-on signal is generated, which appears at the output of the switch-on delay time element only if all the time intervals between the pulses of the recorded frequency are less than the threshold frequency period in

the current set time for inclusion. From the output of the time delay element to the activation, the signal arrives at the single input of the recording trigger and the latter switches.

When the frequency of the pulses at the input of the discriminator decreases, the draining of the threshold pulses at the output of the threshold element 1 stops, and a voltage appears on the tunnel diode 9. The activation signal at the output of the activation time element disappears, the valve element closes. At the same time, a trip signal is generated that appears on

the output of the time-delay element for disconnection only if all the time intervals between the pulses of the recorded frequency are longer than the period of the threshold frequency within the specified delay time for the trip. This time is typically a few threshold frequency periods. Using a resistor 52, the threshold frequency is adjusted to which threshold element 1 is tuned. Since the values of adjustments of the threshold element and time delay elements are connected to one and the same output of the voltage regulator, the constant frequency threshold period is constant. The property of the relative values of shutdown time for shutdown and shutdown. At the same time, the relative values of the time delay for switching on and off can be adjusted with the help of resistors 30, 40. Zener diode

51 determines the lower limit of the threshold frequency in the lowest position of the slider 52.

Subject invention

Discriminator pulse frequency by aut. St. No. 363195, characterized in that, in order to improve noise immunity with significant fluctuations of the pulse frequency, an additional time delay element is introduced in it, the input of which is connected to the output of the frequency-pulse threshold element, and the output is connected to the control input of the valve

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