SU684436A1 - Device for measuring ultrasound attenuation constant - Google Patents

Description

This invention relates to a measurement technique and can be used to measure the attenuation coefficient of an ultrasound. The devices for measuring the attenuation coefficient of ultrasound are known, which include a probe and pulse generator, a receiving-emitting acoustic unit, a visual indication unit, an echo-pulse extraction circuit, an amplitude-amplitude ratio measuring unit, and a recording device i, 2. The use of an electronic oscilloscope in a visual indication unit to identify the number of the selected echo pulse makes the device much more difficult. The closest in technical essence is a device for measuring the attenuation coefficient of ultrasound, containing a series-connected synchronizer, a pulsed high-frequency r. mat, acoustic chamber with transducers, receiver, visual indication unit, selection circuit — selected echo pulses, amplitude ratio measurement unit of selected echo pulses and. recording device sj. The drawbacks of the device are the complexity of visual induction to identify the selected echo pulse using an electronic oscilloscope, and the need to recalculate the attenuation coefficient when the number of the selected echo pulse changes. The aim of the invention is to provide automation of the measurement process. This is achieved by introducing a comparator, a pulse counter, a decoder, a two-way switch, two chains of differentiation, two single-oscillators and a resistor divider into the proposed device, the atom of the comparator is connected to the output of the receiver, and the output of the comparator is connected to the input of the pulse counter, input installation of zero which is connected to the output of the synchronizer, and the outputs of which are connected to the inputs of the decoder, the first output of the decoder is connected through the first differentiating chain to the input of the first vibrator and the other outputs of the decoder are connected to the 5s with. the contacts of one direction-switch, the switching contact of this Direction is connected via a second differentiating chain to the input of the second one-vibrator, the outputs of two single-vibrators are connected to the control inputs of the echo-pulse separation circuit, the contacts of the second direction are connected to the outputs of the resistor divider, and the switching contact of the second direction is connected to registering device. FIG. 1 shows a block diagram of the described device; in fig. 2 voltage plots explaining the operation of the device The device contains a series-connected synchronizer 1, a pulse high-frequency generator 2, an acoustic chamber 3 with transducers, a receiver 4, a comparator 5 and a counter 6 pulses, whose zero input is connected to the output of the synchronizer 1. The outputs of the counter 6 and: POS are connected to the inputs of the decimator 7, the outputs of which, besides the first, are connected to the contacts of the one-way direction of the switch 8. The first output of the decanter 7 and the switching contact of the first direction of the switch The connector 9 is connected via differentiating chains 9 and 10 and one-shot 11 and 12 to the control inputs of the echo pulse extraction unit, for example, in the form of two coincidence circuits 13 and 14, the outputs of which are connected to the inputs of the amplitude ratio measurement unit of the selected echoes pulses made, for example, in the form of two peak detectors 15 and 16 and a differential logarithmic amplifier 17, the output of which includes a recording device 18. The recording device 18 is connected to the switching contact of the second direction bodies 8, which contacts are connected to the outputs p / divider resistor 19. An apparatus for measuring the attenuation factor is as follows Synchronizer 1 generates short pulses at a constant repetition rate {FIG. 2, a). With these pulses, a pulse counter 6 is installed in the O, and a pulsed high-frequency generator 2 is started, which produces a sounding radio pulse, a post | It is fed to the input transducer of the acoustic chamber 3. To the input of the receiver 4, the first impulse passed through the aux 1 (a pulse chamber and a series of echo pulses (Fig. 2, b)), where they are amplified and detected. Comparator 5 forms pulses of a constant pulse from this series (Fig. 2, c) sufficient for normal operation of the pulse counter. When the first pulse arrives at the input of the first pulse, the first output of the deflector 7 is excited, the voltage drop at the first output of the deflector is differentiated by the differentiating chain 9 (FIG. 2, d) and starts one Ovibrator 11, the output pulse of which (Fig. 2, e) arrives at the input of the first circuit coincident 13. In this case, the coincidence circuit transmits the first received pulse of the series (Fig. 2, h), the amplitude of which is remembered by the peak detector 15. Decipher 7 converts the binary code of the counter 6 into the signal at one of its outputs corresponding to the number of the echo pulse B is a decimal numbering system. When the counter counts the number of echo pulses equal to the number of the decoder's switch to which the switching contact of the switch 8 is connected, the signal with this differentiates output of the differentiating circuit 10 (Figure 2, d) and launches odyovibrator 12 whose impulse (FIG. 2, g) opens the coincidence circuit 14, which passes to the input of the peak detector 16 the same echo pulse, the number of which is dialed by switch 8 (Fig. 2, i). The differential log amplifier 17 measures the log ratio of two DC voltages obtained by peak detectors. The current at the output of the differential amplifier:) / where: K: - constant coefficient} amplitude of the first pulse; 2 / «- amplitude of / -echo-41 pulses, If the length of the acoustic base is equal to f. , then in order to obtain the swelling factor, the indicator readings must be divided by the length of the acoustic path; -.1 | DG,, 1-MfoM. . (one). "If each stage of the resolver divider 19 has a weight of 1/2/7, the operation of multiplying by a factor of 1/2 l in the expression (1) is carried out automatically when the switch 8 is switched to the position corresponding to the number of the AND-echo pulse. Invention Formula A device for measuring the attenuation coefficient of ultrasound, comprising a series-connected synchronizer, a pulse high-frequency generator, an acoustic chamber with transducers, a receiver circuit for extracting high-frequency echo pulses, a measuring unit from amplifying the amplitudes of the selected echo pulses, and a recording device, about one liter Of course, in order to automate the measurement process, a comparator, a pulse counter, a decryptor, a two-way switch, two differentials strings, two mono-A and resistor healers, while the comparator input is connected to the Receiver's output, and the Comparator's output is connected to the input of a pulse counter, whose zero input is connected to the synchronizer's output, and the outputs are connected to the decoder's inputs, the first output of the decoder is connected through the first the differentiating chain to the input of the first one-shot; the other outputs of the decoder are connected to the contacts; in one direction of the switch, the change-over contact of this direction is connected via the second connector rentsiruyuschuyu chain to the input of the second monostable multivibrator, the outputs of the two monostable multivibrators connected to the control inputs of circuits isolating the echo pulses, the second guiding pins connected to outputs of the resistor divider, and the second direction change-over contact is connected to the recording device. Sources of information taken into account during the examination 1. USSR author's certificate No. 348933, cl. G- 01 (29/00, 1972. 2. USSR author's certificate No. 535501, Cl. G Oil / 29/00, 1976. 3. R. Truel et al. Ultrasonic methods in solid state physics. M., Mir, 1972 , pp. 264-265 (prototype).

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