SU554523A1 - Device for measuring the time interval between symmetrical pulses - Google Patents

Description

one

The invention relates to the field of measurement technology and can be used in automatic control systems, as well as in impulse locators in cases where it is necessary to determine the time interval between two symmetric impulses, whose amplitudes can vary widely.

A device for measuring the time interval between pulses is known, which contains a generator of filling pulses connected to one of the inputs of the element I, a counting trigger, to the input of which the reference and interval pulses are supplied, the output of the trigger being connected to the second input of the element And pulses.

Prior to the measurements, the trigger is in the "O" position, while the generator pulses arriving at one input of the element I do not pass into the counter. When switching the trigger pulse from the position "About to", the generator pulses go to the counter. Then the interval impulse re-translates the trigger to the position “O. The arrival of pulses in the counter is stopped, and their number, recorded by the counter, determines the value of the desired time interval 1.

 in the known device when unequal changes in the amplitudes of the input pulses and, accordingly, the steepness of their leading edges, the number of counting pulses

varies, which introduces an error in the measurement. Elimination of this pattern by averaging the results of individual measurements reduces the speed of the circuit.

It is also known a device that contains a resonant amplifier and phase-sensitive circuit. The input pulse forms forced oscillations in the amplifier circuit, their phase is rigidly connected with the position on the time axis of the center of gravity of the pulse. Phase-sensitive circuit connected to the circuit,

triggered in a certain phase and gives

the corresponding signal that can

be served on device 2.

The disadvantage of the device is

that in the case of imposition on the input pulse of the chum, the position of the oscillation phase becomes uncertain, which makes it difficult to fix and, accordingly, reduces the measurement accuracy. In addition, the input pulses should not have a flat vertex.

A device for measuring the time interval between symmetrical pulses is known, comprising a digital counter, a pulse generator connected to the input

the first element And through the first trigger to the input of the second element And 3.

However, this device is not high enough performance.

In order to increase speed, the third and fourth elements AND, the threshold amplifier, the second trigger, two OR elements and the NOT element are introduced into the device, the device input being the input of the threshold amplifier whose output is connected to the input of the second trigger with the first input of the third element And, the output of the second trigger is connected through the third element And with the second input of the first element OR, the first input of the fourth element And, the output of which is connected to the input of the first element And, the output the first element OR is connected to the second input of the second element AND directly and through the element NOT - to the input of the fourth element AND, and the second element OR its inputs connected to the output of the first and second elements AND, and the outputs to the input of a digital counter.

FIG. 1 shows a functional diagram of the proposed device; in fig. 2 - stress diagrams.

The device contains a generator 1 pulse filling, the first element AND 2, the first trigger 3 with the counting start, the second element AND 4, the second element OR 5, digital counter 6, the threshold amplifier 7, the second trigger 8 with the counting start, the third element And 9, the first the element OR 10, the fourth element AND 11, the element is NOT 12.

The generator 1 through two channels (the first element AND 2, and the second through serially connected trigger 3 and through element 4) is connected to the element OR 5, the output of which is connected to counter 6. The threshold amplifier 7, whose input is the input of the entire device, is connected at the output with trigger 3, element AND 9 and element OR 10. The output of trigger 8 is connected to the input of element AND II and to the second input of element AND 9, the output of which is connected to the second input of element OR 10, its output is connected to the input of element AND 4 and through the element NOT 12 - to the second entrance of the ele cient AND 11, and the output of the latter is connected to a second input of the AND gate 2.

The device works as follows.

The reference symmetric pulse of any shape (Fig. 2, a, moment to) supplied to the device input is converted at the output of threshold amplifier 7 into a rectangular pulse (for simplicity, the threshold level of the operation of amplifier 7 is taken to be zero) and fed to the inputs of the And 9 elements , OR 10 and trigger 8, which initially is in the state "O (we consider the presence of a pulse as" 1, and the absence as "O). As a result, at both inputs of the element And 9 (and, accordingly, at its output), at the output

element OR 10 and the input element And 11 there is a state of "1. At the same time, at the second input of the element And 11, due to the action of the element NO 12, there will be a “O, with

This element AND 2 is closed for filling pulses, and element 4 is opened and the pulses from generator 1, trigger 3, through the element OR 5 enter counter 6 (Fig. 2, b, interval).

After termination (time ti) of the reference impulse on the first inputs of elements 9 and 9 and 10, the state “O” will appear. At the second input of the element is And 9 and at the input of the element And II is the state "1, since the trigger 8 remains in the same state. As a result, the output of the element OR 10 will be the state "O, the element And 4 is closed, and the element And 2 opens, since at both inputs of the element 11 and 11 the state is" 1.

Thus, the pulses from the generator 1 through the element OR 5 pass into the counter 6 directly without dividing until the moment tzPrn the interval pulse arrives (in Fig. 2a, moment / 2) trigger 8 is transferred to the state "O, element 9" closes. Since the state "1" is present at the same input of the element OR 10, the element 4 and 4 is opened, and the element 11 and 2 are closed. The counter receives filling pulses from generator 1 two times less than during a pause (Fig. 2, b, interval tz- / 3).

At the termination of the interval

impulse (moment ts) on both inputs of the element AND 9 and, respectively, on the second inputs of the elements And 2, 4, the condition "O" occurs, while the filling pulses do not enter the counter 6. With the appearance of the second reference

The cycle will start again. As can be seen from the comparison of FIG. 2, b and c, the number of pulses arriving at the counter during time / o-ti corresponds exactly to the number of pulses that would arrive in the period corresponding to the interval I c ... s between the midpoints of the original signals without prior division.

Thus, the proposed device allows simpler (less complex and expensive blocks - a counter, a trigger) to implement one of the most accurate methods for measuring the time interval. Since the information on the time interval is only in the number of pulses arriving at the counter, you can not pre-record the vertices (middle) of the input signals, and the converter in a certain way is a sequence of counting pulses valid from the beginning of the first input signal to the end of the second, which shortens the measurement time and is lost the measurement process, reduced to a simple count of the number of pulses. The device can be implemented on integrated circuits.

Claims (3)

1. G. Ya. Mirsky, “Measurement of time intervals, 1966, p. 50-52. 2. A.I. Tsitovich “Nuclear radio electronics, 1967, p. 271-276. 3. Copyright certificate № 423095, M. Kl.2 G 04F 10/00, 1972 (prototype). fl iV.fl I I I g I I I I n hnnnnnnnnnnh h Ig | I I I Iiii .1Sh.pdashshshshsh1shI