SU953547A2 - Sound reflection factor meter - Google Patents

Description

one

This invention relates to an acoustic measurement technique using an ultrasonic method and can be used for non-destructive testing of materials.

According to the main auth. USSR No. Y3307 is known for measuring the reflection coefficient of sound, which contains an acoustic long line, two sound receivers, an excitation level control unit, a transducer, a phase-shifting circuit, a phase meter and a phase and level recorder, incident and reflected emission channels, and the output of the incident wave channel connected with a level control unit, and through a phase-shifting circuit with a first input of a phase meter connected to a dc recorder, and the output of the reflected-emission channel is connected to a second input f zometra layer 1 and a recorder.

The disadvantage of the known meter is the impossibility of measuring the input impedance of the sample.

The purpose of the invention is to provide a measurement of the input impedance of the sample.

The goal is achieved by the fact that the meter is equipped with a phase inverter, two adders, the first inputs of which are connected to the output of the phase-shifting circuit, the second input of the first adder is connected to the input of the level recorder, and the second input of the second adder is connected through the phase inverter to the input of the level recorder, an additional phaseometer whose inputs connected to the outputs of the adders, the division unit, two detectors, each of which is connected between the additional phase meter and the division unit, and an indicator whose input is connected to stroke divider.

The drawing shows a block diagram of the meter.

The sound reflectance meter contains an acoustic long line 1, two sound receivers 2 and 3, which emit a transducer C connected to the generator 5 through the excitation level control unit 6, the incident wave extraction channel, consisting of a phase-shifting circuit 7 and a differential amplifier 8, reflected kaial waves consisting of a phase-shifting circuit 9 and a differential amplifier 10,

The output of the differential amplifier 8 is connected to the excitation level control unit 6, and through the phase-shifting circuit P g to the first input of the phase meter 12 connected to the constant current Ies 13. The output of the differential amplifier 10 is connected to the input of the level 1 recorder and the second input of the phase meter 12.

In addition, the meter contains a phase inverter 15, two adders 16 and 17, the first inputs of which are connected to the output of the phase-shifting circuit 11. The second input of the first adder 16 is connected to the input of the level I recorder, and the second input of the second adder 17 through the phase inverter 15 - to the input of the level recorder 14 . The outputs of the adders 16 and 17 are connected to the inputs of the additional phase meter 18. Between the division block 19 and the additional phase meter 18, two detectors 20 and 21 are connected in parallel to each other. The output of the division block 19 is connected to the input of the indicator 22.

The sound reflectance meter operates as follows.

The signal from the output of the phase-shifting circuit 11, proportional to the incident wave fj.i, is fed to the pen inputs of the adders 16 and 17. To the second input of the adder 16, a signal is sent from the recorder 14, proportional to the reflected wave Poff, and to the second input of the 17 The signal from the recorder input is fed through the phase inverter 15.

The output of the adder 16 receives a signal proportional to the magnitude

vibrational ambulance and on the border of sample 23

P - P, by, oip

a phase meter 18 measures the phase of the sample input impedance

 M (W- / RPAG-ROTR) Signals from the outputs of the detectors20

and 21 equal to the modulus of the signals at their inputs

{V ref and fp, P ,, p, y are fed to the inputs of dividing unit 19. At the output of this block, a signal is obtained that is equal to the sample input impedance modulus

Rpad Roth

fOAPotp / i

where 2d - input impedance module

sample;

PC is the medium wave impedance. The proposed meter allows to measure the input impedance of the sample, which expands the functionality.

Claims (1)

1. USSR author's certificate W, cl. G 01 N 29/00, 1973 (prototype).