SU1381353A1 - Apparatus for pulsed excitation of continuous vibrations of a string - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to increase the stability of the string excitation period. Achieving a stable excitation period of the string converter in the device, provided by the constant dividing ratio and generator control scheme, and its independence from the stability of the device circuit parameters allows the excitation period signal to be used as information when building average frequency or its deviation meters with improved measurement accuracy. for string converters having one electromagnet. excitation coil. o (l

Description

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The invention relates to a measurement technique and can be used to excite continuous vibrations of a string of string converters with one electromagnetic excitation coil in a free oscillation mode.

The aim of the invention is to increase the stability of the string excitation period. FIG. 1 shows a block diagram of the proposed device; in fig. 2 - timing charts of the device. The device comprises a string converter 1 with one electromagnetic coil, switch 2, amplifier-limiter 3, 4 pulse generator, digital frequency divider 5, two-input coincidence circuit 6, differentiation unit 7 and recorder 8.

The device works as follows.

The initial start of the pulse generator 4 is provided by applying a start pulse to the input 9 of the device. The developed square-wave excitation pulse from the output of the 4-pulse generator through the switch 2 excites free damped oscillations of the transducer 1 with a period of TC, which is induced in its electromagnetic coil by EMF (Fig. 2a). This signal through the switch 2, the limiting amplifier 3 is fed to the input of the divider 5, the frequency and through the block 7 of differentiation to the second input of the matching circuit 6 (Fig. 2c). At the same time, the first input of circuit 6 of coincidence comes with rectangular pulses from the output of frequency divider 5 (Fig. 2c). From the output of circuit 6, the pulses tied to the null transition of the input signal (Fig. 2d) are fed to the control input of the pulse generator 4, which is generated, at this moment in time, the drive pulse of the string converter 1. Next, the device maintains the string vibrations due to its periodic excitation with a period equal to pT, where n is the frequency division factor. The signal from the output of the amplifier-limiter 3 is fed to the input of the recorder 8.

Achieving a stable excitation period of the string converter in the proposed device, provided by the dividing factor constant n of the generator control circuit and its independence from the stability of the device circuit parameters, allows using the excitation period signal as an information signal, for example,

when constructing meters of the average frequency or its deviation with increased measurement accuracy for string converters having one electromagnetic excitation coil.

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Claims (1)

Invention Formula Device for pulsed excitation of continuous oscillations of a string, comprising a single-coil string converter exciter connected to the first input of the switch, the second input of which is connected to the pulse generator, and the output through a serially connected signal converter and control circuit connected to the control input of the generator, the recorder connected to the output of the signal converter is different in that the excitation period of the string, the control circuit is made in the form of a coincidence circuit in parallel to the inputs of a frequency divider and a differentiation unit whose outputs are connected to the inputs of the coincidence circuit, and a signal converter. :; and it is designed as an amplifier-limiter. ig. 1 gppus. 8 o From 0d FIG. 2