SU410326A1 - - Google Patents

Description

DEVICE FOR DETERMINATION OF THE FREQUENCY RANGE OF HARMONIC SIGNAL ON THE BACKGROUND OF NOISE

one

The invention relates to the field of electrical measuring equipment and can be used to improve the accuracy of digital frequency meters.

A known device for determining the frequency range of a harmonic signal against a noise background, comprising a threshold-level crossing pulse generator, a time relay, a counter, a decoder, valves, pulse drivers, triggers, and a delay unit, is characterized by reduced accuracy.

The proposed device differs from the known ones in that it is equipped with a switch for intersection pulse formation levels, the inputs of which are connected to the output buses and outputs of the flip-flops, the first inputs of which are connected through the first driver of the pulses to the output of the time relay, and the second to the outputs of the valves, the first inputs of which through the delay unit, they are connected to the output of the first pulse former, and the latter to the outputs of the decoder, the inputs of which are connected to the outputs of the counter, the input of the initial state of which is The second pulse shaper is connected to the time relay output, and the counting input is connected to the time selector output, the first input of which is connected to the time relay output, and the second input is connected to the output of the crossing pulse shaper, the first input of which is connected to the input bus, and the second input to exit level switch. This is done with the device to increase its accuracy. The drawing shows a block diagram of the device.

The device consists of a pulse generator crossing the threshold level 1, a gate 2 of the time selector, a pulse counter 3, a pulse former for setting the initial state of the counter 4, a time relay 5, a bus 6 of the command signal consisting of two consecutive pulses, a decoder 7, gates 8 10 triggers

11-13, the switch 14 for the formation of the crossing pulse and output busbars 15, 16, and 17. In addition, the device contains the driver 18 for setting the initial state of the flip-flops 11-13 and the block

delays 19.

The device works as follows. The first signal from bus 6 triggers a time relay 5, which opens valve 2 for the duration of the measurement.

In the preliminary stage of operation of the device corresponding to the first command pulse, counter 3 counts the pulses arriving at its input, the number of which, after the measurement time expires, corresponds to a preliminary estimate of the frequency of the current

signal. The impulse from the imaging unit 18, corresponding to the falling edge of the impulse of the time relay 5, reverses the triggers AND, 12 and 13, and delayed by the delay unit 19 interrogates the decoder 7. The output signal of one of the triggers 11-13 enters the level switch 14. This sets refined pulse driver 1. At the final measurement stage, corresponding to the second command pulse, pulse driver 4 produces pulses from the leading edge of time relay 5, which sets the counter 3 to the initial state. Further, the device operates in the described manner and after the end of the pulse of the time relay, a high potential corresponding to the frequency range of the input signal is established at one of the output strings 15, 16 and 17 of the device.

Subject invention

Device for determining the frequency range of the harmonic signal pa background

noise, containing a threshold-level pulse former, a time relay, a counter, a decoder, a wind, pulse drivers, triggers, and a delay block,

This is due to the fact that, in order to increase accuracy, it is equipped with a non-switch of the levels of formation of intersection pulses, the inputs of which are connected to the output buses and the trigger outputs, the first inputs

which are connected through the first pulse shaper to the time relay output, and the second to the valve outputs, the first inputs of which are connected to the output of the first pulse shaper via a delay unit,

and the second - to the outputs of the decoder, the inputs of which are connected to the outputs of the counter, the input of setting the initial state of which through the second pulse shaper is connected to the output of the time relay, and the counting

the input is to the output of the time selector, the first input of which is connected to the output of the time relay, and the second to the output of the crossing pulse shaper, the nerve input of which is connected to the input bus, and the second to the output of the level selector.

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/five

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