SU1610309A1 - Apparatus for measuring speed of ultrasound - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the speed of ultrasound using the synchro-ring method in various media. The purpose of the invention is to improve the accuracy and the expansion of the measurement range. The device provides an optimal ratio between the duration of the received pulse and the autocirculation period of the sync ring. 3 il.

Description

This invention relates to a measurement technique and can be used to measure the speed of ultrasound in various media. I The purpose of the invention is to increase accuracy and extend the measurement range by ensuring an optimal ratio between the duration of the received pulse and the period of autodynamic synchronization.

FIG. 1 shows a structural diagram of the proposed device; FIG. 2 shows timing diagrams illustrating its operation; FIG. 3 shows the autocirculation waveform depending on the parameters of the detection circuit and the duration t of the train of received and generated pulses.

The device contains series-connected generator T of pulses, radiating 2 and receiving 3 converters, receiving amplifier 4, detector 5 positive half-waves, circuit OR 6, controlled

filter 7, trigger 8 with separate start, synchronized generator 9 and adjustable amplifier 10, the output of which is connected to the input of the pulse generator 1, connected in series with the linear amplifier 11, whose input is connected to the output of the receiving converter 3, block 12, level clamping, detector 13 and DC amplifier 14, the output of which is connected to the second input of adjustable amplifier 10, are connected in series to the detector 15 negative half-waves, the input of which is connected to the output of receiving amplifier 4, inverter 16, forms The pulse generator 17 and the pulse counter 18, the input of which is connected to the second output of the pulse generator 1. The second and third inputs of the trigger 8 are connected respectively to the ladies of the inverter 16 and the driver 17 pulses, the second output of which is connected to the second input of the circuit

but:

about with

about )

316

IGO 6, and the second input of the controlled filter 7 is connected to the output of the detector 5 positive half-waves.

The device operates in the following manner. When turned on, the synchronizing generator 9 generates an electrical pulse, which, having passed the adjustable amplifier 10 and the generator 1, is amplified and fed to the radiating converter 2, causing generation and radiation of the acoustic pulse to the medium.

The acoustic impulse, after passing through the medium under investigation, is received by the receiving transducer 3, converted into an electrical impulse in it, amplified by the receiving amplifier 4, then converted by the detector 5 positive half-waves and simultaneously; but is converted by the detector 15 of negative volvoln, as a result of which, at the outputs of the detectors 5 and 15, a signal is obtained, consisting respectively of positive and negative half waves.

Then the signal from the detector 5 output goes to the first input of the OR 6 circuit and to the second input of the adjustable filter 7. When the first positive half-wave occurs, the OR 6 circuit turns off the adjustable filter 7 and the half-wave of the pulse passes to the first input of the trigger 8 with separate start, causing it to trigger .

At the same time, the signal from the output of the detector 15 negative half-waves is fed to the input of the inverter 16, inverted by it and fed to the second input of the trigger 8, causing its secondary triggering, the same signal is also fed to the input of the former 17, which produces a long rectangular pulse, the duration exceeds the received pulse train, thereby blocking the trigger 8 from firing from the subsequent half-waves of the train, i.e. trigger 8 becomes insensitive to input signals on the first and second inputs.

The inverse (second) output of the driver 17, the signal is fed to the second input of the OR circuit 6, which, when this signal appears, activates an adjustable filter 7.

The pulse from the output of the trigger 8 is applied to the input of the synchronized generator 9. and starts it.

ten

03091

Thereafter, the auto-cycling cycle of the signal is repeated.

During operation, the clock pulses from the output of the receiving converter 3 are also fed to the input of the linear amplifier 11, amplified by it without restriction, and fed to the input of the level clamping unit 12, adjusted so that the control signal at its output appears only if the specified signal is exceeded / noise at the inputs of amplifiers 4 and 11. From the output of block 12, the signal enters the input of detector 13, is detected in it and is further amplified by direct current amplifier 14, from the output of which the signal goes to the second input of the controlled amplifier 10, the gain of which is maximal when there is no signal at the output of amplifier 14 of direct current.

20

five

0

five

0

As a result, the voltage at the output of the generator 1, and hence the power supplied to the radiating transducer 2, is functionally dependent on a given optimum useful signal at the output of the receiving transducer 3, i.e. the signal-to-noise ratio at the output is kept stable.

FIG. Figure 2 shows the timing diagrams of the autocirculation signals at the corresponding points a, b, c, d, e, f, g, h of the block diagram of the device shown in FIG. 1, where T is the period of auto-circulation of signals; t ,. five

 C

the duration of the received pulse train, s, t is the current time; and - voltage.

FIG. Figure 3 shows the autocirculation waveform depending on the parameters of the detection circuit and the duration of the generated pulse.

Circuit parameters are expressed through

t. tsuga received and

50

I rc t,

five

where r

WITH

t,

resistance of the signal detection circuit;

capacitance of the signal detection circuit} the duration of the train of received pulses;

Ubx

161

voltage, respectively, at the output and input of the signal detection circuit.

Claims (1)

Invention Formula A device for measuring the speed of ultrasound, containing a series-connected synchronized generator, an adjustable amplifier, a pulse generator, an emitting and receiving transducers, and a receiving amplifier, serially connected a linear amplifier whose input is connected to the output of the receiving transducer, a constant-level amplifier current, the output of which is connected to the second input of the adjustable amplifier, and the pulse counter, the input of which is connected to the second output of the pulse generator all different 1610309 the fact that, with a chain of increasing the accuracy and expansion of the measurement range, it is equipped with a series-connected positive pulse wave detector, an OR circuit controlled by a filter and a trigger with a separate start and a series-connected negative half-wave detector, invert Q r to the pulse shaper - The leads of the positive and negative half-wave detectors are connected to the output of the receiving amplifier, the second input of the controlled filter is connected to JJ detector output positive vsShln, the inverter output is connected to the second trigger input with separate start, the third input of which is connected to the first output of the driver 20 pulses, the second output of which is connected to the second input of the OR circuit, and the trigger output with separate start is connected to the input of the synchronized generator. 25 FIG. g 2 .3  J3 t.Mff