SU1747937A1 - Contactless vibrometer - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure vibration parameters and mechanical movements in various fields of science and technology. The purpose of the invention is to expand the dynamic range of vibration measurement and improve measurement accuracy. A device for contactless measurement of vibration parameters contains a microwave generator 1, an antenna-feeder path 2 with arms of a reference 3 and a reflected 4 signals, to which a phase detector 8 and a recorder 13 are connected. In order to broaden the dynamic range of the measured parameters and increase the sensitivity, delay dispersion line 12 connected to the reflected signal circuit 4, controlled phase shifter 6 connected to the reference signal circuit 3, control unit 11 connected between the phase detector 8 and the phase shifter 6, and the recorder 13 is connected between the control unit 11 and the phase shifter 6. 1 sludge. yo

Description

The invention relates to measuring equipment and can be used to measure vibration parameters and mechanical displacements in various fields of science and technology.

The purpose of the election is to expand the dynamic range of vibration measurement and increase sensitivity.

This goal is achieved in that in a device containing a microwave generator, an antenna-feeder path with directional couplers of the reference and reflected signals, a phase detector and a registrar, a dispersion delay line is introduced, 10 connected between the directional coupler and the phase detector of the reflected signal, an electrically controlled phase shifter connected between the directional coupler of the reference signal and the phase Detector, a control unit connected between the phase detector and the phase shifter.

The proposed connection allows you to expand the dynamic range of measurement of vibration parameters, i.e. significantly increase the maximum possible range of mechanical vibrations. In addition, in this case, it becomes possible to increase the accuracy of measurements, as well as the ability to register the Doppler components of the spectrum of the microwave signal generated by the vibration of the object, and, consequently, the speed of its movement.

The drawing shows a diagram of the proposed device.

The device contains a microwave generator 1,

A device for non-contact measurement of object vibrations, containing generators; emitting and receiving antennas, mixers, a comparison circuit and a recording device. From the generator, the signal is fed to the mixer and the emitting antenna, the reflected signal from the vibrating surface, modulated in phase and frequency through the receiving antenna and amplifier, is also fed to the mixer. The resulting difference signal is fed to a comparison circuit, which also receives a difference signal from an identical second transmitter-receiver device. From the comparison circuit, the resulting signal is fed to the recorder. ;

A device for non-contact measurement of oscillations is also known, which contains a microwave generator, an antenna-feeder path with two phase detectors located at a quarter of the wavelength in the waveguide of the balanced amplifier and recorder, and a 30 standing wave is formed between the generator and the vibrating surface with a varying electric field in places are tired. antenna-feeder path 2, directional. branching is proportional to the amplitude of the vibrations. The signals received by the detectors are fed to the balanced amplifier and from it to the recorder.

'The disadvantage of these devices is the narrow dynamic range of measurement of vibration parameters.

The closest to the proposed technical essence is a device for non-contact measurement of the parameters of mechanical vibrations, including a microwave generator, an antenna-feeder path, containing a phase detector with an energy branch 45 and a recorder operating on the principle of modulation of the standing wave amplitude.

A disadvantage of the known device is also the small dynamic measurement range, which is due to the fact that the phase detectors used have a nonlinear characteristic, which can be considered linear only with small phase changes. As a result, the amplitude 55 of the vibration fluctuations must be much less than the wavelength of the probe signal in order to obtain a Minimal claim; compression of the parameters of mechanical vibrations.

taps 3 and 4, valve 5, electrically controlled phase shifter 6, mixers 7 and 9, phase detector 8, local oscillator 10, control unit 11, dispersion line 12. delays registrar 13.

An antenna-feeder path 2 is connected to the microwave generator 1 with directional couplers 3 and 4, between which a valve 5 is connected. The directional coupler 3 of the reference signal is connected through a controlled phase shifter 6 and mixer 7 to a phase detector 8, to which also through mixer 9 and a dispersion 1 ^ delay line connected to a directional coupler 4 of the reflected signal. Both mixers are connected to the local oscillator 10, the output of the phase detector through the control unit 11 is connected to a controlled phase shifter 6 and a recorder 13.

The device operates as follows.

The microwave generator 1 creates in the antenna-feeder path 2 and in the free space between the antenna and the vibrating surface a microwave field consisting of incident and reflected waves. Part of the incident wave through the directional coupler 3 and phase shifter 6 is fed to

1747937 6 mixer 7, which also receives the signal from the local oscillator 10. The resulting differential signal IF1 is fed to the phase detector 8. Another part of the incident wave passes through the valve 5 and the system and, being reflected from the vibrating surface, is modulated in phase and frequency . The reflected wave through the system and the directional coupler 4 enters the dispersion Line 12, and from it to the mixer 10, to which the signal from the local oscillator 10 is also fed. The resulting differential signal of the IF2 is fed to the phase detector

8, in which the phases of the difference signals IF1 and IF2 are compared. If they match 15, the error signal will be zero. The larger the phase difference, the greater the error signal. The error signal is fed to the input of the control unit 11, which, under its influence, supplies a potential to the controlled phase shifter 20, which tunes the phase shifter and changes the phase of the incident wave so that it becomes equal to the phase of the reflected wave, and the error signal at the phase detector becomes zero, 25 The same the potential is supplied to the recorder 13. By including the dispersion delay lines 12 into the path of the reflected signal between the coupler and mixer 9, translation of other '30 Plerovian shifts of the microwave carrier frequency is achieved catch arising due to certain velocity of the vibrating surface in a significant shift of the reflected signal phase, going to the mixer 9 to 35 further comparison with the phase of the reference signal mixer 7 by means of the phase detector 8.

'. ·' ·. · ’·. '' 40

Thus, the proposed device allows you to monitor the phase change of the modulated signal. The setup constantly works on the linear section of the phase detector characteristics, regardless of the amplitude of the vibration, and also allows recording Doppler mixes of the carrier frequency of microwave oscillations, and from these mixes, therefore, determining the velocity of the vibrating surface. In addition, the sensitivity of measuring vibration parameters increases due to the transition to intermediate frequencies IF1 and IF2 when comparing the phases of the incident and reflecting signals with a phase detector.

Claims (1)

Claim A device for non-contact measurement of vibration parameters, comprising a microwave generator, an antenna-feeder path with directional couplers of the reference and reflected signals, a phase detector and a recorder, which is necessary in order to expand the dynamic range of the measured parameters and sensitivity, it is equipped with a dispersion delay line, the input of which is connected to the output of the directional coupler of the reflected signal, and the output to the input of the phase detector, electrically controlled by a phase shifter, the input to torogo connected to the output of the directional coupler a phase detector reference signal, a control unit having an input connected to the output of the phase detector, and an output - to parallel vklyuchennym'registratoru and phase shifter.