SU1170288A1 - Device for measuring ultrasound velocity - Google Patents

Abstract

A ULTRASONIC MEASUREMENT DEVICE, containing a series-connected generator, ultrasonic emitter, ultrasonic receiver, amplification and shaping unit and frequency control unit, the output of which is connected to the control input of the generator, a divider with a division control factor, a frequency meter with an indicator for counting the ultrasound speed and A key, characterized in that, in order to expand the frequency range, it is provided with a series-connected divider. the input of which is connected to the key, the first input of which is connected to the generator, counter, code converter, comparison unit and gating with a generator, the output of which is connected to the second input of the counter, sequentially connected by a multiplication unit, the input of which is connected to the output of the code converter, and the memory register , the output of which is connected to the second input of the comparison unit, the control unit, the first output of which is connected to the second input of the memory register, the second output to the second input of the gated rator generator, the third the output is with the second key inlet, the fourth output is with the first input of the frequency meter, and the input is with the first output of the frequency meter, while the divider input with a controlled division factor is connected to the generator output, the output is connected to the second frequency counter input, and the third key input P1 is connected to the first output of the frequency meter.

Description

one

The invention relates to a measurement technique and can be used in devices designed for digital measurement of the velocity of propagation of ultrasound.

The purpose of the invention is to expand the frequency range.

The drawing shows a device for measuring the speed of ultrasound.

The device for measuring the speed of ultrasound contains a series-connected oscillator 1, an ultrasonic emitter 2, an ultrasonic receiver 3, a gain and shaping unit 4 and a frequency control unit 5, the output of which is connected to the control input of the generator 1, a divider 6 with a control division factor, frequency meter 7 with indicator 8 for counting the speed of ultrasound, key 9 in series connected divider 10, the input of which is connected to the key 9, the first input of which is connected to generator 1, counter 11, converter 12 code, b Comparison block 13 and strobe generator 14, the output of which is connected to the second input of counter 11, are connected in series to the multiplication unit 15, the input of which is connected to the output of code converter 12, and memory register 16, the output of which is connected to the second input of comparison 13, 13 control, the first output of which is connected to the second input of the memory register 16, the second output to the second input of the strobe generator 14, the third output to the second input of the key 9, the fourth output to the first input of the frequency meter 7, and the input to the first output of the frequency meter 7, The input of the divider 6 with the control division factor is connected to the output of the generator 1, the output is connected to the second input of the frequency meter 7, and the third input of the key 9 is connected to the first output of the frequency meter 7. f

Speed measuring device

Ultrasound works as follows.

The generator 1 produces a high-frequency voltage, which is converted by the ultrasonic emitter 2 into an ultrasonic wave, which, propagating in chamber 18 and partially reflected from the ultrasonic receiver 3, is transformed by it into electrical oscillations. When the frequency of the radiation is equal to the frequency of the acoustic

The chamber resonance 18, the voltage on the ultrasonic receiver 3. rises to its maximum value. This voltage is amplified by the block 4

5 amplification and shaping. Block 5

frequency control provides continuous dynamic tuning of the oscillator 1 to acoustic resonance

with frequency f.,. .-P

O The ultrasound velocity in chamber 20 is determined by the formula

2 f p - 1

WITH

n - a

de f - frequency of acoustic resonance of the camera; 1 — chamber length; n is the number of half-waves of ultrasound laying along the length

cameras;

a is the correction caused by a frequency independent phase shift in the reflection of ultrasound from an ultrasonic receiver, and

emitter 2 and 3. A correction is determined by the formula

and ,, - -Л 2

(one)

but

 Where

H -arctg. (Z-tg.; (2)

0

h - phase angle in the reflection of ultrasound from the ultrasonic transducer (receiver 3 or emitter 2);

L - ultrasonic thickness

converter (receiver 3 or radiator 2);

Z is the specific acoustic impedance of the ultrasonic transducer (receiver 3 and radiator 2);

C (j is the ultrasound velocity in

ultrasonic transducer (receiver 3 or emitter 2).

2jiLL: oifu device value

is defined as follows.

Pulses with frequency f are fed from generator 1 through key 9 and divider 10 with a division factor k into counter 11. After a predetermined time 4t has elapsed, counter 11 will have 2 I-bo-1-n pulses when the condition of time marks 4t is counted proportionally to the time stamp period frequency counter 7, which is set using the time base unit 19 included in the total time clock, and control block 17. When a code of a specific number is supplied from the output of counter 11 to the input of converter 12 of the code, the tangent code of this 2 J. LO fn number is obtained at the output of the latter. The output code tg ---- is multiplied by the Z code in block 15 multiplication. The result of the multiplication is recorded in the memory register 16 and is fed to the second input of the comparison unit 13. At this time, the counter 11 is reset to zero. The contents of the counter 11 begin to increase again from zero to equality of the codes of the numbers at the output of the converter of the 12 code and the register 16 of the memory. If the codes are equal, comparison unit 13 generates a signal that blocks the gating (generator 14. Now at the output of comparison unit 13, as in register 16 of memory, the code AND tg .JlLli C is fixed. The same code is found at the output of code converter 12. On its input and output of counter 1 is / -7 t 2T-Lefn arctg (Z -tg - ;-). To have the contents of counter 11 proportional to the variable correction a, defined by the specified formulas. To account for the signs and the fixed part of the correction According to the formula (2), the output of the counter 11 is connected to the input of the divider 6 with the equal dividing factor in such a way that when the frequency changes from 0 to resounding frequency of the transducer which corresponds to the angle V O - l, the division ratio of dslitol 6 with controlled dividing ratio changes from the magnitude, the transmission coefficient fop n-1, to values proportional to n + 1, i.e. change of the correction a modulo not more than 2. Prior to the start of measurements, the value of n is set for the case of an ideal interferometer, equal to C. After the installation of coagulum 1) d; Lenn p-a, in divider 6, the control signal ({) dividing the division from the fourth output of block 17 of the control section gives a signal to the first BXI (center 7). In frequency meter 7, block P) The time slot produces a certain a time base for closing the selector 20 included in the frequency meter and for closing the key 9 via its third input. The pulses from the output of the divider 6 with the control division factor are fed to the second input of the gastrometer 7 through the selector 20 with a frequency f n ---, from the output of which they arrive at indicator 8, made in the form of a counter, the reading of which will be equal to the value of the speed O of ultrasound. From the third b1 | G.; ode, the control block 17 outputs signals to the second input of the key 9 for performing closing and opening operations. The signals from the first and second outputs of control unit 17 control the second input of memory register 16 and the second input of the strobe generator 14. Using an ultrasound velocity measuring device allows the frequency spectrum of the SRI to be expanded by taking into account the correction caused by the frequency-dependent phase shift during ultrasound reflection from ultrasonic transducers.

Claims (1)

DEVICE FOR MEASURING THE SPEED OF ULTRASOUND, containing a series-connected generator, an ultrasonic emitter, an ultrasonic receiver, a gain and shaping unit and a frequency control unit, the output of which is connected to the control input of the generator, a divider with a control fission factor, a frequency meter with an indicator for counting the speed of ultrasound and a key, characterized in that, in order to expand the frequency range, it is equipped with a series-connected divider, the input of which is connected to the key, the first input to is connected to a generator, a counter, a code converter, a comparison unit, and a gating generator, the output of which is connected to a second counter input connected in series to a multiplication unit, the input of which is connected to the output of the code converter, and a memory register whose output is connected to the second input of the comparison unit, a control unit, the first output of which is connected to the second input of the memory register, the second output with the second input of the gate generator, the third output with the second key input, the fourth output with the first the input of the frequency meter, and the input with the first output of the frequency meter, while the input of the divider with a controlled division factor is connected to the output of the generator, the output is with the second input of the frequency meter, and the third key input is connected to the first output of the frequency meter. >