SU433623A1 - DELAY LINE ON ULTRASONIC SURFACE WAVES - Google Patents

Description

I1

The invention relates to the field of pulsed technology and can be used. Vano in various radio devices, devices for delay and circulation of radio pulses.

I The known delay line in the form of a polyhedron made of single-crystal quartz with electroacoustic transducers of surface ultrasonic waves has significant internal losses. ri, due to the ineffectiveness of the excitation of bulk waves of counter-current converters; Acquiring the circulation of an acoustic volume wave in the sound duct is difficult.

The purpose of the invention is to reduce losses and increase the delay time of the ultrasonic wave conduit circulating around the perimeter.

This is achieved by the fact that the planes of the faces located along the perimeter of the polyhedron are oriented along the X and Zi planes of the quartz single crystal, with the transition regions between the faces being rounded.

FIG. 1 shows the view of the delay line; in fig. 2 is a schematic representation of the orientation of the sides of the sound guide; in fig. 3 - area of transition between the faces in an enlarged form, i Delay lines on ultrasonic surface waves is a conduit 1 in the form of a hexagon of regular or irregular shape from single-crystal quartz, on the faces 2-7 of which electroacoustic transducers 8-1О are applied (other converters, located on the face of x 5, 6 and 7j in Fig. 1 are not marked) surface ultrasonic waves in the form of, for example, interdigital structures. One of the transducers, for example 8, is input. On the end surfaces of the polyhedron 1 there are through holes a and a hole b filled with an acoustic absorber and an electrically conductive material that have electrical contact with the metallized end surfaces of the polyhedron.

Planes of faces 2-7 located

jjo to the perimeter of the polyhedron, are oriented by the X X Z imprint of a monocrystalline quartz and form a closed surface,

the length of which in the direction of the axes X (see Fig. 2) determines the maximum | 1th signal delay, the transition areas between the faces are rounded off (see Fig. 3), the extent of the cylindrical surface of the individual transition 11 is measured in the direction of wave propagation, is determined by the arc of the AB, the altogether part of the circumference, the radius of which is chosen from the condition R (5i6) X .. where R is the radius

acoust

rounding, L

- acoustic length

acoust

ultrasonic wave. The rounding radius is the same for all six transitions. Under this condition, the surface of a separate transition is a part of the surface of a cylinder of radius R. The total length of the surfaces of the transitions, taking into account the reduced ratio, is 1 s 6 x

MB 2LG (5-6) L

acoust

: Ultrasonic surface wave,

radiated by the input transducer 8, i spreads around the perimeter of polyhedron 1 as if it spread on the surface of the UX-cut quartz plate except for the transition regions and between the faces.

I At the output transducers 9 and 10, when a surface wave passes, an electrical signal arises and is removed from them. Due to the small non piezoelectric coupling in quartz, the energy changes in the acoustic wave as it passes under the transducers can be neglected. After passing all the faces of the polyhedron, the acoustic wave either extinguishes with the help of an absorber applied to face 2 or begins to circulate around the perimeter of the polyhedron, gradually fading due to the loss of energy in the wave from various causes.

Input converter 8 along with An elastic surface wave excites waves that propagate into the volume of the polyhedron and cause it. the appearance of spurious signals on output converters. In addition, undesired electromagnetic coupling may occur due to capacitance between the input and output converters. To reduce capacitive between converters and scatter volumetric

The waves are made through holes a and b, filled with an acoustic absorber and an electrically conductive material that performs the aeol of the acoustic and electromagnetic screen. Such a screen can be fasteners, for example, bolts through holes in a polyhedron.

Subject invention

Line delay on ultrasonic surface waves on. Based on an acoustic conductor in the form of a polycrystal made of microcrystalline quartz with electroacoustic transducers of surface ultrasonic waves, characterized in that, in order to reduce losses and increase the delay time of the ultrasonic wave circulating around the perimeter of the acoustic conduction of the polyhedron, they are oriented along XZ planes quartz single crystal, with the transition between the faces being rounded.

eight

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ten

five/

FIG. 2

Fig.Z