SU1486919A1 - Acoustic emission signal simulator - Google Patents

Description

The invention relates to non-destructive testing and can be used in the control of products by acoustic emission signals for their mode 2

lyirovaniye. The purpose of the invention is to improve the accuracy of the simulation of acoustic emission signals. On the modulator 10. serves the carrier frequency and the envelope signal. The envelope is formed using a series-connected high-frequency generator 1, a shaper of 2 rectangular pulses, a coincidence element 4, a counter 5 and a decoder 6, an OR element 8 and an envelope detector 9, as well as voltage dividers connected between the corresponding outputs of the decoder 6 and the inputs of the OR 8 element The pause between simulated acoustic emission acts sets the shaper 12. 2 Il.

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The invention relates to non-destructive testing using acoustic emission (AE).

 The purpose of the invention is to improve the accuracy of imitation.

FIG. 1 is a block diagram of the device; in fig. 2 - version of the pause driver.

The device consists of a series-connected high-frequency generator 1, a shaper of 2 rectangular pulses, a frequency divider 3, a coincidence element 4, a counter 5 and a decoder 6, whose η outputs through η voltage dividers 7 are connected to η inputs of the OR element 8, the output of the latter is connected C detector 9 envelope with one of the inputs of the modulator 10, the other input of which is connected to the output of the generator 1, and the output of the modulator 10 is connected to the input of the attenuator 11, in addition, the output of the last discharge of the counter 5 is connected to the input form Ate 12, the output of which is connected to the second input of the element 4 matches.

Shaper 12 pause consists of multivibrator 13 and KZ-trigger 14, and the output of multivibrator 13 is connected to the 3-input trigger 14, Kvhod which is the input of shaper 12 pause, and its output is the output of KZ-trigger 14.

The device works as follows.

The generator 1 signals, whose frequency corresponds to the carrier frequency of the simulated AE signal, are fed to the input of the modulator 10 as the carrier frequency of the modulated signal, and to the shaper of 2 rectangular pulses, from the output of which the rectangular signals of the same frequency participate in shaping the envelope of the simulated pulse AE. The pulse envelope signal AE is periodically fed to the second input of the modulator 10, at the output of which a simulated signal is formed, which is controlled by the level of the attenuator 11 and is fed to the input of the calibrated AE equipment. The envelope of the simulated signal AE is formed as follows. The signals of the rectangular carrier frequency are fed to frequency divider 3, the division ratio of which depends on the ratio of the carrier frequency of the signal and the spectral composition and the duration of its envelope.

Impulses from divider 3 have frequency

where £ _p - carrier frequency output

10 generator 1;

K - the division ratio of the divider

frequencies.

Signals with a frequency of £ d through an open element 4 matches arrive at

15 counter 5, the outputs of which are connected to the inputs of the decoder 6, at each of the η outputs - which alternately, starting from the lower order, level "1" appears. Moreover, "1" is present only on one of the η outputs.

decoder. Each of the outputs of the decoder is connected to its divider.

• 7 voltage, the output of which the operator sets this level

25 so that the envelope at the output of detector 9 of the envelope repeats the shape of the real AE signal. The position of the potentiometer sliders (voltage dividers 7) approximates the shape of the source signal, which is more accurate, the greater the number of them. It was established experimentally that for most practical purposes the number η can be chosen not

35 is greater than 15. The envelope thus formed is fed to the second input of the modulator 10. The pause between the simulation pulses AE is formed as follows. When in the counter

40 5 comes, for example, the last pulse, i.e. an overflow pulse appears in its last discharge, it enters the E-input of trigger 14 and sets the value 45 at its output, which creates a prohibition on the passage of pulses from generator 1 to counter 5 and resets it to 0, t. -e stops the formation of the next pulse envelope. Multivib50 rator 13 generates short pulses with a controlled repetition period, and the next such impulse, applied to the 3rd input of the trigger 14, sets "1" at its output, thereby opening the coincidence element 4. Begins the formation of a new pulse envelope. Thus, their repetition period depends on the repetition period of self-oscillating multivibr pulses5

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Torah. The device can operate in a single mode, if the start is carried out manually (instead of the multivibrator 13) or from an external generator (for example, from a generator of loading cycles).

Claims (2)

Claim 1C 1. An acoustic emission simulator containing a series-connected high-frequency generator, a modulator and an attenuator, characterized in that, in order to improve the simulation accuracy, it is equipped with a series-connected shaper of rectangular pulses, the input of which is connected to the output of the high-frequency generator, is divided. 2C Lem frequency, coincidence element, a counter and a decoder, connected in series by an OR element and an envelope detector, the output of which is connected to the second input of the modulator, voltage dividers connected between the corresponding outputs of the decoder and the inputs of the OR element, and a pause generator connected between the output of the last digit of the counter and the second input of the match item. 2. The simulator for π. '1, which differs from me in that the pause driver is made of a series-connected multivibrator and KTrigger, the K-input and output of which are respectively the input and output of the pause driver. in