SU1150730A1 - Acoustic phase shifter - Google Patents

Abstract

An ACOUSTIC PHASOVER contains a sound conductor made in the form of a polyhedron, on one inclined face of which an input transducer is placed, and on another inclined face - an output transducer and electrodes connected to the output of a control voltage source, characterized in that In order to reduce power consumption, the sump is made of a cubic paraelectric.

Description

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The invention relates to electronics and can be used in acoustoelectronic signal processing devices.

An acoustic phase shifter is known, which contains a sound pipe with input and output converters and electrodes placed on it, connected to the output of a control voltage source, and a layer of liquid crystal 1 is introduced under the control electrode.

The disadvantage of this phase shifter is the complexity of its design.

Also known is an acoustic phase shifter containing a sound conductor made in the form of a polyhedron, on one inclined face of which an input transducer is placed, and on the other inclined face is an output transducer, and electrodes connected to the output of a control voltage 2

The disadvantage of this acoustic phase shifter is significant power consumption.

The aim of the invention is to reduce power consumption.

The goal is achieved by the fact that in an acoustic phase shifter containing a sound pipe made in the form of a polyhedron, on one inclined face of which an input transducer is placed, and on another inclined face - an output transducer, and on the corresponding plane-parallel faces there are electrodes connected to voltage, sound. the wire is made of cubic paraelectric.

FIG. 1 and 2 shows the design of the phase shifter; in fig. 3 shows the dependence of the phase f of the reflected acoustic wave on the angle of its incidence os for several values of the coefficient of electromechanical coupling K of the material of the acoustic duct.

The acoustic phase shifter contains a conductor 1, an input transducer 2 and an output transducer 3. The sound conductor 1 has plane-parallel reflecting faces 4 and 5, electrodes 6 and 7 connected to the output of the control voltage source 8, the electrodes 6 and 7 can cover completely two opposite faces 4 and 5, be placed along the edges of one (Fig. 1) or several reflecting faces (Fig. 2), and also be performed on the reflecting faces x 4 and 5 in the form of opposing pins.

The sound duct 1 (or, in any case, its thin layer lying on the reflecting

Gran x 4 and 5) is made of a cubic paraelectric, for example, BaZg / TUz solid solutions, PbSr / TiOa, K / Ta Nb / O, whose Curie point lies below the operating temperature of the phase shifter.

Acoustic phase shifter works as follows.

An acoustic wave, which enters the sound pipe 1 from the input transducer 2 or from another acoustic device, propagates in the sound pipe 1 perpendicular to the input face. Due to the inclination of this face, the wave falls on face 4, is reflected from it and either directly (Fig. 1) or after a number of additional reflections between

5 plane-parallel faces 4 and 5 (Fig. 2) falls on face C with output transducer 3. At the same time, the angles of incidence and reflection of the wave are equal to the angle of inclination of the faces. The angle of inclination of the indicated faces to the reflecting face 4 of the duct 1 lies in the range of 45-85 °, preferably 70-80 °. The dimensions of the conduit 1 must be such that the acoustic wave entering into it from the input transducer 2, reflected from faces 4 and 5, hits the center of the edge of the output transducer 3.

The electrodes 6 and 7 are supplied with a control voltage from a source 8. The electric field induces a piezoelectric effect in the material of the duct 1. In the absence of a control voltage, cubic paraelectrics do not have a piezoelectric effect and their electromechanical coupling coefficient, K 0. grows, reaching values of about 0.5.

A change in the coefficient of electromechanical coupling by a control voltage leads to a change in the velocity of ultrasound V in the material of the duct and

the result is a change in the phase difference of the acoustic wave at the output and input of the phase shifter, equal to w w / where frequency; I is the full path length of the acoustic wave in the sound duct. The second reason for the change in the phase of the passing wave of the control voltage is a change in phase i at the time of reflection from the faces, which is equal to r 2arctg (K tgoc). Total restructuring phase 4 DM.

0 This provides an increase in the steepness of the adjustment characteristic of the phase shifter, leading to a decrease in the control voltage and a corresponding reduction in power consumption.

5 This acoustic phase shifter, as can be seen from FIG. 3, in the region of preferred incidence angles of about 70 ° C to 80 ° C, it is possible to achieve a phase adjustment of about 90 °.

one reflection when K changes from O to 0.5.

In acoustic phase shifters with multiple reflections, phase reorganization

increases in reflection times. The control field is at the same time 2 MV / m. Power consumption in phase hold mode is almost absent.

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Claims (1)

ACOUSTIC PHASOR REDUCER containing a sound duct made in the form of a polyhedron, on one inclined face of which an input transducer is located, and on the other inclined face is an output transducer, and electrodes connected to the output of a control voltage source are placed on corresponding plane-parallel faces, characterized in that, for the purpose reduce energy consumption, the sound pipe is made of cubic paraelectric.