SU1315793A1 - Method and apparatus for measuring object vibrations - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the amplitude-time parameters of acoustic oscillations. The purpose of the invention is to improve the measurement accuracy by achieving the phase mismatch of the interfering beams as the detuning signal of the working point using the second interference pattern, and also by the device stabilizing the optical phase of the interferometer when the intensity of the laser beam is changed. The radiation passes through the beam splitter 2 and falls on the mirrors 3 and 4, fixed respectively on the piezoelectric transducer 5 and 6, which are fixed on the piezoelectric transducer 7. The rays reflected from the mirror 4 and the object 13 form the first interference pattern projected on the photodetector 8. The rays reflected from The mirrors 3 and the object 13 form the second interference pattern, which is recorded by the photodetector 9 connected to the negative feedback system 11 connected to the piezoelectric transducer 5 and determining the signal oglasovani and second phases of the interference pattern from a point 2t1G. The system 1 1 produces a control signal to the piezoelectric transducer 7, which stabilizes the operating point of the interferometer, and the phase of the first interference pattern is regulated by the voltage of the source 12. 2 s.p. f-ly, 1 ill. ; (/: l with SAE

Description

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The invention relates to a measurement technique and can be used to measure the amplitude-time parameters of acoustic oscillations.

The purpose of the invention is to improve the measurement accuracy by using the phase mismatch of the interfering rays as the detuning signal of the working point using the second interference pattern.

The device ensures the stabilization of the optical phase of the interferometer with a change in the intensity of laser radiation.

The drawing shows a block diagram of a device for carrying out the proposed method.

The device contains a laser 1, a beam splitter 2 arranged successively during radiation, mirrors 3 and 4, piezo transducers 5 and 6 arranged in the same plane, on which mirrors 3 and 4 are attached, respectively. Piezo transducers 5 and 6 are fixed to a piezo transducer 7 During the course of reflected from beam splitter 2 Photoemitters 8 and 9 are located in the radiation. The photodetector 8 is electrically connected to the registration unit 10, and the photodetector 9 is connected to the negative feedback system 11, the outputs of which are connected to the piezoelectric transducer 5 and 7. Source The nickname 12 of the adjustable reference voltage is electrically connected to the piezo transducer 6,

The device works as follows.

The laser beam expanded to the necessary diameter is directed to the beam splitter 2, where it splits into two beams, one of which is reflected from object 13 and the other from mirrors 3 and 4, the beam reflected from mirror 4 and the beam reflected from the surface object 13, form the first interference pattern, which is projected onto the photodetector 8, and the rays reflected from the mirror 3 and from the surface of the object 13, form the second interference pattern, which is projected onto the photodetector 9 connected to the negative feedback system, given in the form of an extremal regulator and including a reference frequency generator 14. When applied to the piezoelectric transducer 5 from the generator 14 sinusoidal voltage

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the intensity of the second interference pattern is modulated with the frequency UQ and a sinusoidal output is produced at the output of the photoreceiver 9

an electrical signal whose frequency and phase depend on the phase of the interference pattern. If the phase of the interference pattern is exactly 2in ir, then the frequency of the electrical signal

of the receiver 9 is equal to 2 (0, if the phase is not equal to 2m ii, then the component has a component with frequency W, and the phase of this component relative to the phase of the reference frequency of the generator 14 is determined by the sign of the deviation of the interference pattern from the point of tp 2t P. System 1 1 negative feedback extracts the signal from the photodetector 9 signal with

frequency CO ,,, compares the phase of this signal with the phase of the reference signal and generates a control signal that is fed to the piezoelectric transducer 7 to adjust the phase at the point

.

Thus, a rigid stabilization of the phase of the second interference pattern occurs. The phase of the first interference pattern is rigidly associated with

the phase of the second picture, since the piezoelectric transducers 5 and 6 are fixed on the piezoelectric transducer 7, and can be smoothly controlled by a constant controlled voltage from the source 12.

Claims (2)

1. A method for measuring an object's vibrations, consisting in the fact that form the interference pattern, adjust the phase difference of the interfering beams, select and stabilize the operating point of the interference pattern and measure the oscillation parameters object to change the parameters of the interference pattern, which differs from the fact that, in order to increase the measurement accuracy, they form the second interference pattern, connect both interference patterns in phase and stabilize the working point of the interferometer according to the phase difference of the interfering rays of the second picture, equal to 2iii iT where m is an integer. 2. A device for measuring the oscillations of an object containing a laser, arranged in series along the course of an emission. 3113157934 The beam splitter, the sparkler, is a piezo-former, on which is fixed a transducer on which a second mirror is fixed, by a source regulated by a mirror, located on the move from a constant voltage, connected to a subcluster (worn from a beam splitter emitting to the second piezoelectric transducer connected electrically to a photoreceiver, any second photoreceiver, optically the negative feedback system associated with the second mirror through the output of which is connected to the piezo-beam splitter and electrically - to the Slolo, and the registration unit, about which registration, the third piezo-transforming by the fact that, with the aiming device, on which are fixed Improved measurement accuracy, first and second piezo transducers, it is equipped with a second mirror, connected to the negative system during radiation in plane-feedback, which is performed in of the first mirror, the second piezopreform of the extremal controller.