SU422097A1 - DEVICE FOR MEASURING TIME INTERVALS - Google Patents

Description

one

This invention relates to a pulse technique and can be used to measure time intervals.

A device for measuring time intervals is known, comprising a pulse shaper, a differentiation circuit, triggers, key devices, a reference frequency generator, a switch and a pulse counter, the outputs of the reference frequency generator are connected via a switch to the input of key devices.

This device has a low accuracy of measuring time intervals.

The purpose of the invention is to improve the accuracy of measuring time intervals.

For this, the output of the differentiation circuit is connected to the counting inputs of the flip-flops, one of the outputs of which is connected to the control input of the key devices, while the output of the key devices is connected to the input of the pulse counter.

FIG. 1 shows a block diagram of the proposed device; FIG. 2 - diagrams of his work.

A device for measuring time intervals contains a pulse former 1, a differentiation circuit 2, triggers 3 and 4, key devices 5 and 6, a generator

7 reference frequency, the switch 8 and the counter 9 pulses, valves 10 and 11.

The output of generator 7 is connected via switch 8 to the inputs of key devices 5 and 6. The output of differentiation circuit 2 is connected via gates 10 and 11 to the counting inputs of triggers 3 and 4, one of whose outputs is connected to the control input of key devices 5 and 6. Outputs of key devices 5 and 6 are connected to the input of the counter 9 pulses.

FIG. 2 accept the following notation:

a - video pulses at the output of the imager 1;

b - the time interval during which the key device 5 is open;

in - the time interval during which the key device 6 is open;

g - pulses at the output of the counter 9 pulses.

The device works as follows.

The pulse shaper 1 is designed to generate pulses from input pulses of the same amplitude with steep edges.

A differentiation circuit 2 is connected to the output of the pulse former 1. The pulses corresponding to the leading edges of the signals under study are fed through the valve 10 to the counting input of the trigger 3, and the pulses corresponding to the rear edges come through the valve 11 to the counting input of the trigger 4.

Triggers 3 and 4 adjust the state of key devices 5 and 6, which represent notional impulse-sharing schemes. Depending on which key is open, from generator 7 through switch 8, the pulses are sent to the input of counter 9.

The switch 8 is designed to send even pulses of the generator 7 to the input of the key device 5, and odd impulses to the input of the key device 6. As the switch 8 you can use, for example, a ring binary counter with two outputs.

Thus, in the time interval between the leading edges of the pulses under study, even pulses of the generator 7 arrive at the input of the counter 9, and in the time interval between the rising fronts - the odd numbers of the oscillator of the generator 7. pulses are received with a frequency equal to half the frequency of the generator 7, and in the time interval between the falling edge

the first pulse and the leading edge of the second pulse to the input of the counter 9 receives pulses with a frequency equal to the frequency of the generator 7.

It can be proved that the number of pulses counted by counter 9 is proportional to the time interval between the centers of the pulses under study. In the timing diagram of FIG. 2, this interval is labeled X.

Subject invention

A device for measuring time intervals, comprising a pulse former, a differentiation circuit, triggers,

key devices, a reference frequency pulse generator, a switch and a pulse counter, the output of a reference frequency pulse generator connected via a switch to the input of key devices, characterized in that, in order to improve the measurement accuracy of time intervals, the output of the differentiation circuit is connected to counting inputs Triggers, one of the outputs of which is connected to the control input of key devices, while the output of key devices is connected to the input of a pulse counter.