SU640221A1 - Ultrasonic oscillation propagation time measuring apparatus - Google Patents

Description

of the discriminator whose threshold input is connected to the output of the memory circuit, a k-ro pulse selector (k 2, 3, .., t) is entered, the counting input of which is connected to the output of the amplitude discriminator, the synchronization input is connected to the output of the generator, the output is connected to the reference input of the time interval meter, and the signal input of the amplitude discriminator is connected to the output of the ultrasonic oscillation receiver.

Such an embodiment of the device provides a measurement of the propagation time of ultrasonic vibrations at the moment of arrival of the k-ro pulse of a sequence, the level of discrimination for which is proportional to the amplitude of the first pulse of the same sequence. As a result, the amplitude fluctuations of the signals of adjacent sequences do not lead to the appearance of a dynamic error in the formation of the discriminator response threshold, which results in an increase in the accuracy of measurements of the propagation time of ultrasonic vibrations.

In the drawing, a fuctional diagram of a device for measuring the time of propagation of ultrasonic vibrations is represented.

The device contains a transmitting path consisting of a series-connected generator / and emitter 2, and a receiving path consisting of a series-connected receiver 3 of ultrasonic vibrations, a selector 4 of the first half-period of ultrasonic vibrations and a memory circuit 5, as well as an amplitude discriminator 6, a selector 7 k-ro imp) ls (k 2, 3..., t), and meter 8 time interval. The threshold input 9 of the amplitude discriminator 6 is connected to the output of the memory circuit 5, the signal input 10 to the output of the receiver 3 of ultrasonic vibrations, and the output is connected to the counting input 11 of the selector of the 7th pulse. The input 12 of the synchronization of the selector pulse is connected to the output of the generator /, and the output is connected to the input 13 of the reference meter 8 time interval, the input 14 of which is connected to the output of the generator /.

The device works as follows.

Using the emitter 2, ultrasonic oscillations are emitted into the medium, which, having reached the receiver 3 of the ultrasonic vibrations, are converted into electrical signals. The selector 4 selects the first half period from the signal sequence, and the memory circuit 5 generates a constant voltage that determines the response threshold of the amplitude discriminator 6, which is proportional to the amplitude of the first half period. Amplitude discriminator 6 forms of sequences of sinusoidal oscillations

sequences of rectangular pulses that arrive at the counting input 11 of the selector 7 of the k-ro. impulse. Using the meter 8 time interval, the time interval between the arrival of the signal at the reset input 14 from the generator / and th pulse to the input 13 of the reference is determined. The systematic error in measuring the propagation time of ultrasonic

The oscillations caused by the readout of the i-th pulse can be taken into account if the frequency of the received oscillations and the number of the impulse to which the readout is made is known.

Since by the moment of arrival of the pulse of each sequence, the threshold of amplitude discriminator 6 has already been formed by the scheme of 5 memories proportional to the amplitude of the first half-period of the same sequence, the amplitude fluctuations of the signals of neighboring sequences do not lead to the dynamic error of the threshold of amplitude discriminator 6.

Thus, a device for measuring the propagation time of ultrasonic vibrations makes it possible to increase the measurement accuracy during amplitude fluctuations of signals. It can be used to accurately measure the speed of propagation of ultrasonic vibrations, distances in environments with variable attenuation of acoustic waves, echolocation of obstacles with variable reflectance of ultrasound, as well as echolocation of fast-moving objects.

Claims (2)

Invention Formula Device for measuring the propagation time of ultrasonic vibrations containing a transmitting path consisting of a series-connected generator and emitter, and a trigger path consisting of successively connected ultrasonic oscillations receiver, a selector of the first half-period of ultrasonic vibrations and a memory circuit, and also a time interval meter, the reset input of which is connected to the generator output, and amplitude discriminator, threshold the input of which is connected to the output of the memory circuit, characterized in that, in order to increase the measurement accuracy during amplitude fluctuations of the signals, a k-ro pulse selector (/ fe 2, 3, ..., t, the counting input of which is connected to the output of the amplitude discriminator, the synchronization input is connected to the generator output, the output is connected to the reference input of the time interval meter, and the signal input of the amplitude discriminator is connected to the output of the ultrasonic oscillation receiver. Sources of information taken into account during the examination: L1VI .J-IJt i - - 1. Gorbatov A. А., Rudashevsky G. Е. Acoustic methods and means of measuring distances in air. L1., “Energy, 1973, p. 111-115, 118-120, 126-128, 130-132, 134-139. 2. USSR author's certificate i L 402734, cl. G 01 B 17/00, 19/1.