SU1573446A1 - Device for shaping duration of pulse burst - Google Patents

Abstract

The invention relates to a measurement technique and, in particular, can be used in devices for measuring parameters of acoustic emission signals. The aim of the invention is to improve the accuracy and enhance the functionality by using two identical time delay circuits and realigning their constant counting clock frequency. The use of identical shutter speeds made of a counter and a trigger and a variable clock frequency eliminates errors in the formation of the beginning and end of the duration of an unknown burst, the parameters of which vary widely. 2 Il.

Description

The invention relates to a measurement technique. In particular, it can be used in devices for measuring parameters of acoustic emission signals (AE).

The purpose of the invention is to improve the accuracy and enhance the functionality by eliminating the error in forming the beginning and end of a burst and adjusting the counting of the time delay circuits.

FIG. 1 shows a block diagram of the device; in fig. 2 - timing charts of the device.

The device contains a pulse former with a normalized front, the input of which is the device input, prohibition circuit 2, the short pulse generator 3 serially connected and the first time delay circuit 4, the second one identical to the first time delay circuit 5, made

the counter 6 (7) and the trigger 8 (9), the S-input of which is connected to the R-input of the counter 6 (7) and is the first input of the time k circuit (5), the counting input of the counter 6 (7) its second input , the trigger output 8 (9) is its output, the first input of the second time delay circuit 5 is connected to the output of the pulse shaper 1 with the normalized front, the second input to the second input of the first time delay circuit and the clock frequency bus F, the output to the first the input of the prohibition circuit 2 and the input of the imager 3 short pulses, the second input of the prohibition circuit 2 is connected to the output of the first There is a delay in circuit A, and its output is the output of the device.

Positions 10-15 designate the outputs of the signals from the units of the device for forming the duration of the pulse bursts.

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with

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The device works as follows.

A signal in the form of a burst of pulses or, for example, an acoustic emission signal 10, which is actually a radio pulse, arrives at the pulse shaper 1, which forms a series of pulses of constant amplitude and duration. The leading edge of the first pulse from the pulse train 11, the trigger 9 is set to one, the same packet pulses arrive at the R input of counter 7. Thus, the counter 7 counts the time pulses F only during the time intervals between the pulses of the capacitance N of the counter and the period The clock frequency F is chosen so that its overflow time and the appearance of a pulse at its output is greater than the minimum possible duty cycle of pulses 11 inside the packet and shorter than the minimum possible duration between bursts of pulses.

After the last pulse of the stack expires, an overflow pulse appears at the output of counter 7, which returns trigger 9 to the initial state. At that, the duration of the output pulse 12 of the flip-flop 9 is equal to the duration of the burst of pulses plus the counting constant of the circuit

5 time lag equals.

F

The accuracy of this constant setting is proportional to the capacity of the meter.

6 (7).

On the leading edge of the output pulse 12 of the trigger 9 by the shaper 3, a short pulse 13 is generated, which triggers the trigger 8. Through

time span equal to

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the overflow pulse of the counter 6 returns the trigger 8 to the initial state. At the same time, at the output of the trigger 8, a pulse 1A is generated with a duration 50 equal to the constant counting time of circuit A (5). For the duration of the pulse 1, the pulse from the output of the trigger 9 is forbidden through the circuit 2 of the ban.55

At the output of the prohibition circuit 2, a pulse 15 is obtained with a duration exactly equal to the duration of the input burst of pulses 10, and delayed by a time equal to the constant counting time of the circuit (5). The identity of the counters 6 and 7 and the total clock frequency F for them ensure the exact subtraction of the constant count. By changing the clock frequency F, it is possible to adjust the value of the constant counting circuit k (5) of the time delay over a wide range.

Thus, the proposed device allows to provide a high accuracy in the formation of the duration of an unknown burst of pulses and has the ability to adjust the constant counting of the time delay circuit when the parameters of the input signals vary within wide limits.

Claims (1)

Invention Formula A device for forming a pulse burst duration, containing a normalized front pulse shaper, whose input is the device input, a prohibition circuit and a short pulse pulse shaper connected in series and the first time delay circuit, characterized in that, in order to increase the accuracy and expansion of functional capabilities, it is equipped with a second, identical to the first, time delay circuit made of a serially connected counter and a trigger, the S input of which is connected to the R input of a counter a is the first input of the time delay circuit, the counting input of the counter is its second input, the trigger output is its output, the first input of the second time delay circuit is connected to the output of the pulse shaper with the normalized front, the second input is to the second input of the first time delay circuit and the clock frequency bus, the output to the first input of the inhibit circuit and the input of the short pulse driver, the second input of the inhibit circuit is connected to the output of the first time delay circuit, and its output is the device output.