SU547688A1 - Device for measuring acoustic attenuation - Google Patents

Description

3

The aim of the invention is to increase TO UIOCJ and measurement speed.

This is achieved by connecting one output of the receiver through a linear transducer, accumulating and controlling elements with an electric pulse counter, the other with an amplitude discriminator connected to the controlled element and through an integrator, a threshold circuit to the trigger trigger input, the other input of which is connected with the start-up generator, and the output of the clock pulse generator is connected to the trigger trigger output and the electrical pulse counter input through a key circuit.

FIG. 1 shows a block diagram of the device; in fig. 2, 3 - timing diagrams for the device operation.

The device contains a clock pulse generator I, a key circuit 2, a generator of 3 high frequency pulses, a trigger trigger 4, a generator of 5 trigger pulses, a variable delay 6, acoustic sensors 7.8 with sample 9, a threshold circuit 10, a gate driver 11, an electrical receiver 12 signals, integrator 13, electric pulse counter 14, linear transducer 15, amplitude 1Y distortion 16, accumulation element 17, control element 18.

A generator of 3 high frequency pulses controlled by a clock pulse generator 1 produces high frequency pulses that are converted by the acoustic sensor 7 into ultrasonic oscillations. Ultrasonic oscillations of the prokhot t through sample 9 and, repeatedly reflected from the faces of sample 9, are transmitted to the receiving acoustic sensor 8, converted into electric oscillations, amplified, detected in the receiver 12 electrical signals and in the form of aaiyxarouijix video pulses are fed to the inputs of the linear transmitter 15 and amplitude discriminator 16 (see Fig, 2, graph. 1,2,3).

From the one of the first video pulses of the series, selected by the variable delay 6, the strobe former 11 and the linear transducer 15, the capacitor of the accumulator element 17 is charged to the amplitude value of the pulse and its subsequent discharge to the controlled element 18 (Fig. 2,1-raf 4) .

Thus, with each clock pulse to the inputs of the amplitude discriminator 16, a series of damped pulses and a capacitor discharge curve (an exponential signal) simultaneously arrive.

In the initial state of lm by the time of launching the measuring part of the device, the parameter of the controlled element 18 corresponds to the maximum resistance, and the slope of the discharge curve of the capacitor to the minimum attenuation.

The trigger pulse from the generator 5 trigger pulses transfers trigger 4 trigger, which otpgegaet key circuit 2 at the input of the counter

electric pulses 14, which transmit pulses from the generator 1 clock pulses. The counter code 14 changes the parameter (resistance) of the controlled element (code-to-resistance converter) 18. At the same time, the resistance is increased by one cycle. quantization and, therefore, a change in the slope of the capacitor discharge curve corresponds to the increment of the number in the counter 14 by one pulse.

Thus, on the amplitude discriminator 16, periodic bending of the bend of each series of reflected signals (pulses) with the capacitor discharge curves occurs and at the time they coincide with the integrator 13 of the amplitude discriminator 16, the number of pulses of the series exceeding the level of the curve discharge within the threshold of sensitivity of the ASCt discriminator 16. Threshold circuit 10 generates a signal that returns trigger trigger 4 to its original position, key circuit 2 closes (see fig. 2, graph. 5-8). According to the state of the electric pulse counter 14, which recorded the number of clock pulses per measurement cycle, the numerical value of the measured value (ultrasound absorption coefficient) is judged (see Fig. 2, graph 9).

The process of measuring the attenuation of ultrasound in the sample under study is explained by time diagrams (see Fig. 3):

where OSD - the initial value of the absorption coefficient;

DoC is a discrete variation of the switch; oijj is the desired absorption coefficient.

Claims (2)

Invention Formula A device for measuring the attenuation of acoustic oscillations, containing high-frequency clock and trigger pulse generators, acoustic sensors, electrical signal receiver, storage element, linear transmitter, control element, amplitude discriminator, integrator, threshold circuit, trigger trigger, key circuit, variable delay , a gate driver and an electric pulse counter, characterized in that, for the purpose of improving accuracy and measuring speed, one output of the receiver is connected n through a linear oscillator, accumulative and controlled elements with an electric pulse counter, another with an amplitude of the discriminator connected to the controlled element and through an integrator, a threshold circuit to the trigger trigger input, D) the second input connected to the trigger generator, and the output of the clock pulse generator through the key coe / auieii circuit with the trigger trigger trigger output b and the electrical pulse counter input. Sources of information taken into account during the examination: 5 fi 1. Nosov V.А. Design of ultrasonic measuring equipment, M. 1972, p.113. 2. Truell R. et al. Ultrasonic methods in solid state physics, M., Mir, 197Z, c.69 (prototype). FIG. 2 Fig 3