SU1516796A2 - Acousting receiver - Google Patents

Abstract

The invention relates to ultrasound technology and can be used, for example, in sonar. The purpose of the invention is to increase the reliability of the receiver by eliminating self-excitation when working with narrow radiation patterns. The receiving membranes 1 and 9 when an acoustic wave falls on them begin to oscillate with a phase shift. Laser interferometers 2 and 10 and photodetectors 3 and 11 register these oscillations. The generator 6 of rectangular pulses periodically breaks the feedback circuit of amplifier 4 with membranes 1 and 9 using key 5. 2 Il.

Description

/

cl

H:

and

U

ten

/ 77777

I

tmisi,

cl

Od

sl

CD O)

eleven

P

 GO

ot.f

The invention relates to acoustic and ultrasound technology, can be used, for example, in hydrolic and other areas of technology based on the use of vibrations in various environments for location and diagnostics, and is an improvement of the device according to the main author. St. No. 1388731.

The purpose of the invention is to increase reliability by eliminating self-excitation when working with narrow radiation patterns.

FIG. 1 shows a block diagram of an acoustic receiver; in fig. 2 - a series of timing diagrams illustrating his work.

The receiver consists of a receiving membrane 1, a laser interferometer 2, a photodetector 3, an amplifier 4, an electronic key 5, a generator of 6 square pulses, a frequency doubler 7 of the piezoceramic rod 8, an additional membrane 9 of the laser interferometer 10, a photodetector 11 and an amplifier 12.

The receiver works in the following way.

When a plane acoustic wave is incident on the surface of the receiving membranes 1 and 9, they begin to oscillate with a certain phase shift, which depends on the angle of incidence, the acoustic wave and the distance between the phase centers of the membranes. The vibrations of the membrane 1 are recorded using a laser interferometer 2 and a photodetector 3 connected to amplifier 4. The output of amplifier 4 via electronic key 5 and frequency doubler 7 is connected to piezoceramic rod 8, which excites membranes 1 and 9. The chain of these elements forms back coupling circuit, the transmission coefficient in which is set equal to 1, At this, the periodic self-excitation of oscillations of the receiving membranes 1 and 9 begins, which is carried out due to the variable tension produced by the piezoceramic m rod 8. The electronic switch 5 under the influence of the generator 6 periodically changes the transmission ratio of the feedback loop connection, so that oscillations occurred srt meme

branes The frequency of the generator 6 should be about 100 times lower than the frequency of the signal.

FIG. Figure 2 shows the variable diagrams characterizing the operation of the device: a - a randomly varying acoustic signal, b - voltage from generator 6, c - resulting oscillations of the membrane 9, recorded with the help of an interferometer 10, a photodetector 11 and an amplifier 12. From FIG. 2 that each oscillation pulse starts with the amplitude that the signal had at that moment, and the maximum amplitude of the oscillations is proportional to the amplitude of the signal. Thus, the oscillations of the receiving membranes 1 and 9 are amplified. The initial vibrations of the membranes 1 and 9 occur in the Melada phase, which depends on the angle of incidence of the acoustic wave and on the distance between the phase centers of the membranes. This leads to the dependence of the gain on the angle of incidence of the acoustic wave for the membrane 9. The dependence of the gain on the angle of incidence of the acoustic wave allows the required radiation pattern to be formed by changing the gain of the feedback loop. The closer the loop transfer coefficient is to 1, the narrower the radiation pattern. The technical solution implements the operation of the device with a feedback loop transfer coefficient of one, which provides an extremely narrow radiation pattern.

In comparison with the known, the proposed acoustic receiver ensures stable operation in the formation of extremely narrow radiation patterns.

Claims (1)

Invention Formula Acoustic receiver auth. St. No. 1388731 distinguishing it is equipped with a series-connected square pulse generator and an electronic switch, the second input of which is connected to the amplifier output, and the output to the frequency doubler input. Fm.g