SU1185079A1 - Device for measuring the linear movements - Google Patents

Abstract

A DEVICE FOR MEASURING LINEAR DISPLACEMENTS containing fixed and movable piezoelectric plates, interdigital transducers located on them, a generator connected to the inlet of an interdirectional transducer of a fixed piezoelectric plate, absorbers and a meter / phase difference whose first input is connected to the output of the generator, phase It is distinguished by the fact that, in order to increase accuracy, it is equipped with an additional counter-pin converter located on the mobile piezoelectric a plate at a quarter-wavelength distance from an interdigital transducer of a mobile piezoelectric plate, sequentially connected by a phase shifter with a 7F / 2 angle of rotation, the input of which is connected to the output of an interdigital transducer of a mobile piezoelectric plate, and an adder, the second input of which is connected to the output of an additional counter -the pin converter, the receiver, and the output with the second input of the phase difference meter.

Description

The invention relates to a measuring technique and can be used to measure linear displacements. The purpose of the invention is higher accuracy. FIG. Figure 1 shows schematically the proposed device for illustrating linear displacements; in Figure 2, time diagrams. The device contains fixed and movable piezoelectric plates 1 and 2, located on them interdigital transducers 3 and 4, a generator 5 connected to the input of an interdigital transducer l 3 fixed piezoelectric plate 1, absorbers 6-9, meter 10 phase difference, the first the input of which is connected to the output of the generator 5, is complementary to the counter-to-voltage converter 11 located on the mobile piezoelectric plate 2 at a distance of a quarter of the wavelength from the counter-converter 4 under Thermal piezoelectric plate 2, sequentially connected phase shifter 12 with a rotation angle of 71/2, the input of which is connected to the output of the counter-pin converter 4 movably plate 2, the adder 13, the second input of which is connected to the output of the additional counter-pin converter 11, and the output is the second input of the meter 10 phase difference. The device. For measuring linear displacements works as follows. When applying the excitation voltage from the generator 5, the counter-pin converter 3 excites an actual wave. The latter extends in both directions from the counter-pin transducer 3 along the surface of the stationary piezoelectric plate 1 92 of the plate 1. A part of the direct surface acoustic wave is received by the counter-pin transducer 4 of the moving plate 2 and the additional counter pin converter 11, and a part of the wave is reflected from the end of the fixed piezoelectric plate 1 and the end of the movable piezoelectric plate 2. The reflected waves are received by an additional interdigital transducer 11 and the counter piece A gray transducer 4 of the mobile piezoelectric plate 2. The counter-pin converter 4 of the mobile piezoelectric plate 2 receives a direct acoustic wave, the KOTOpof view is shown in FIG. 2 Due to the fact that the counter-pin converter 4 is connected to the first input of the adder 13 via the phase shifter 12 with a rotation angle of 77/2, a signal is supplied to the first input of the adder 13, the phase of which has the form shown in FIG. 2s. Since the center of the additional interdigital transducer 1 1 is set at a distance from the center of the interdigital transducer 4, the signal arriving at the second input of the adder 13 has the form shown in FIG. 2c. As a result, a sum signal is applied to the input of the phase difference meter 10 (Fig. 2i.). When receiving the reflected acoustic waves by additional and interdigital transducers 11 and 4, signals are input to the input of the adder 13, the phases of which differ on the TG, which leads to their compensation. The use of the device makes it possible to increase the measurement accuracy by excluding the arrival of a reflected signal on the phase difference meter, which carries information about the measured displacement.

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Claims (1)

DEVICE FOR MEASURING LINEAR MOVEMENTS, comprising a fixed and movable piezoelectric plate, interdigital transducers located on them, a generator connected to the input of the interdigital transducer of the fixed piezoelectric plate, absorbers and a phase difference meter, the first input of which is connected to the generator output, which is different the fact that, in order to improve accuracy, it is equipped with an additional interdigital transducer located on a movable piezoelectric layer not at a quarter of the wavelength from the interdigital transducer of the movable piezoelectric plate, connected in series with a phase shifter with a rotation angle of 7G / 2, the input of which is connected to the output of the interdigital transducer of the movable piezoelectric plate, and an adder, the second input of which is connected to the output of the additional interdigital pin converter, and the output with the second input of the phase difference meter. J 12 CGK ---- SU, 1185079