SU957031A1 - Device for forming random vibrations - Google Patents

Description

(54) DEVICE FOR THE FORMATION OF RANDOM

VIBRATION

The invention relates to testing equipment, namely, devices for generating random vibrations. A device for generating random vibrations is known, comprising a series-connected noise generator, a driver comprising a set of bandpass filters, AGC amplifiers, an adder, a power amplifier and an exciter, a feedback circuit including a vibration sensor, a set of analysis filters connected to the output of the vibration sensor, comparison units The outputs of which are connected to the control inputs of the AGC amplifiers 1. The device allows to form a spectrum of random vibrations, however, the accuracy of the formation is low, that Fishing vzaimovli Niemi forming channels. The closest to the invention in its technical essence is a device for generating random vibrations, comprising a series-connected white shum generator, an adder and an electrodynamic vibration exciter, a vibration sensor, feedback circuits, each of which includes a band-pass filter connected to the output of the vibration sensor, a dispersion meter the comparison unit, the AGC amplifier, whose control input is connected to the output of the comparison unit, the signal input to the output of the bandpass filter, and the output to the adder, the line 3 2. The device forms a spectrum of random vibrations, eliminating the mutual correlation of the signals at the input of the adder. The latter is achieved due to the fact that the signals to the input of the adder arrive with a shift in time. However, the accuracy of the formation of the spectrum by the device is reduced due to the stable harmonic oscillations that occur during testing. The aim of the invention is to increase accuracy. This goal is achieved by the fact that in each feedback circuit a delay line is connected by an input to a vibration sensor, and an output is connected to a bandpass filter. The drawing shows the block diagram of the device. A device for generating random vibrations contains a series-connected white noise generator 1, an adder 2 and a vibration oscillator 3, a vibration sensor 4, feedback circuits (not indicated).

each of which includes a delay line 5, a band-pass filter 6, a dispersion meter 7, a comparison unit 8 and an AGC amplifier 9, whose control input is connected to the output of the comparison unit 8. The signal input of amplifier 9 is connected to the output of the corresponding bandpass filter b, and the output to the adder 2.

The device works as follows.

The signal generator 1 white noise through the adder 2 is fed to the input of the exciter 3 oscillations. The vibration sensor 4 converts the mechanical oscillations into an electrical signal, which, through the delay lines 5 and the band-pass filters 6, goes to the inputs of the dispersion meters 7 and in feedback to the inputs of the AGC amplifiers 9. The signals from the outputs of the disperse meters 7 are fed to one of the inputs of the comparison units 8, the second inputs of which receive the reference signals from the output of the program master (not shown). The error signals from the outputs of the comparison units 8 are fed to the control inputs of the AGC amplifiers 9. From the outputs of the amplifiers 9, the feedback signals are fed to the inputs of the adder 2 and summed with the signal of the white noise generator 1.

To suppress a harmonic signal having a period To and input, for example, to the inputs of the first and second feedback circuits, in the second circuit, a signal delay is set to t KTo + + -, where K is a positive integer. In this case, the harmonic signals of these circuits will be fed to the input of the adder 2 in antiphase.

At the same time, for the random components, the feedback is positive, since the variance of the sum of the signals of the feedback circuits and the signal of the white noise generator, de-correlated by delay lines 5, is equal to the sum of their variances.

The invention enhances the accuracy of shaping the spectrum of random vibrations by suppressing the harmonic components that occur during the testing process.

Claims (2)

1. Klyuev V.V. Instruments and systems for measuring vibration of shuma and impact. Reference book. 2. M., “Maschinostroenie, 1978, p. 173. 2. USSR author's certificate in application number 2990176 / 25-28, cl. G 01 M 7/00, 1980 (prototype).