SU654893A1 - Ultrasound velocity measuring device - Google Patents

Description

one

The invention relates to the field of acoustic measurements and can be used to automatically measure the velocity of propagation of ultrasound in liquid, solid and gaseous media.

A device is known for measuring the speed of ultrasound in media containing a starter generator, a probe pulse generator, a receiving-transmitting transducer, an amplifier, a selector, a driver, a frequency meter, a key stage, and a gating pulse generator.

The disadvantage of it is low measurement accuracy.

The closest in technical essence is a device for measuring the speed of ultrasound, containing a series-connected probe pulse generator, a receiving and transmitting transducer, an amplifier, a delay line, a gate pulse generator, and a matching stage, the second input of which is connected through the time selector to the output of the probe pulse generator 2 .

The disadvantage of it is low measurement accuracy.

The aim of the invention is to improve the measurement accuracy.

For this, the proposed device is equipped with a start generator, an assembly circuit connected between the start generator output and the probe probe generator input, a prohibition cascade, the first input of which is connected to the output of the coincidence cascade directly, the second input through the pulse counter, and the output to the input of the assembly circuit , an additional cascade of coincidence, the first input of which is connected to the output of the cascade of coincidence, the second input - to the output of the counter, the second input of which is connected to the output of the starting generator, meter time interval included between the start and the additional generator output stage coincidence and limiter amplifier, connected between the third input of the coincidence stage and the second output

booster.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 and 3 are temporary diagrams that illustrate the operation of the scheme. The device contains sequentially

connected start generator 1, circuit 2 assemblies, probe pulse generator 3, receiving-transmitting converter 4, amplifier 5, delay line, 7 gate pulses generator, cascade

8 Coincidence, the second input of which is connected through the time selector 9 to the output of generator 3, counter 10 and cascade AND ban, the first input of which is connected to the output of cascade 8 coincidence, and the output to the input of circuit 2 of the assembly. A matching stage 12 is also connected to the output of the coincidence stage 8, the second input of which is connected to the output of the counter 10, the input of which is connected to the output of the starting generator.

Between the outputs of the starting generator 1 and the cascade 12 of coincidence, a time interval meter 13 is turned on. Between the third input of the cascade 8 coincidence and the second output of the amplifier 5, the limiting amplifier 14 is turned on.

The time selector 9 is made in the form of a trigger 9-1, one input connected to the output of the generator 3 directly, and the other through the delay line 9-2.

The device works as follows.

Starting generator 1 pulses 15 (see Fig. 2) through the circuit 2 Assembly starts the generator 3 probe pulses, which excites the primary-transmitting transducer 4 and starts the time selector 9.

At the same time, the starting generator 1 of pulses 15 resets the counter 10 to the initial state 16 and starts the time interval meter 13, which starts a discrete count of the time interval 17, 18. The ultrasonic signal after the receiver goes to the amplifier 5. From the amplifier output, the signal 19 is fed through the line 6 of the delay. generator 7 strobe pulses. The generated gating pulses are applied to the first input of the cascade 8 coincidence, the second input of which receives a signal from trigger 9-1, which blocks the cascade 8 to coincide from the effects of electromagnetic and reverberation interference by an amount equal to the delay time of the pulse 20 to the delay line 9-2. The third input of the cascade 8 coincidence receives the signal 21 from the amplifier-limiter 14.

On the steepest front of the signal 21, by means of the gate voltage 22 and the selection voltage 23, the cascade 8 coincides with the output pulse 24, which comes through the cascade 11 ' prohibition, the assembly circuit 2 to start the generator 3 probe pulses. The autocirculation process continues.

At the same time, the pulses 24 from the output of the cascade 8 coincidence are fed to the input

the cascade 12 coincidence and the input of the counter 10, which closes the prohibition and the opening cascade 12 coincidences with an “-pulse” cascade 12 16. The impulse of the l + 1 cascade 8 coincidences a time interval meter 13, which counts the time interval proportional to the speed of ultrasound propagation. The time interval during which autocirculation is stopped and there is a pause is allotted to the attenuation of the increased reverberation

interference that provides high stability.

The invention makes it possible to increase the measurement accuracy by suppressing the reverberation noise occurring in an acoustically investigated medium.

Claims (2)

1. USSR author's certificate No. 461362, cl. G 01N 29/04, 1973. 2. USSR author's certificate No. 480975, cl. G 01N 29/04, 1971. i il i,. c. Uuljuli u Sh Juj iiilJ Uu , t, t tz t.tj ij 27 I in fig.Z