SU463223A2 - Line delay elastic surface wave - Google Patents

Description

one

The invention can be used in radio devices for various purposes.

The known delay line of the elastic surface wave in the ed. St. No. 433623.

The known delay line cannot delay the signal by time exceeding the time of a single propagation of the elastic surface wave around the perimeter of the sump.

The purpose of the invention, the extension of the signal delay, is achieved by the fact that in the proposed delay line the plane of one of the six side working faces of the single crystal quartz sound duct is parallel to the crystallographic axis X and tilted to the axis Z.

FIG. 1 shows the delay line, open, full view; in fig. 2 is a section of the chute with a plane coinciding with the YX plane of a single crystal of quartz, which is perpendicular to the plane of the inclined face; in fig. 3 is a side sweep of the hexagon with interdirectional transducers; in fig. 4 - skew of the wave front as it passes along an inclined face.

The delay line of the elastic wave surface (Fig. 1) is a suction line 1 made of monocrystalline quartz in the form of a hexagon, correct or irregular.

the shapes, whose side faces 2-6 are oriented along the XZ planes of the quartz single crystal, and the side face 7 is parallel to the ZX crystallographic axis and is inclined to the axis

Z; 8 - bottom line.

Input transducer 9 is located on face 2, output transducers 10-13 are located at gran x 3-6, respectively. The electrodes of the output transducers are angled with respect to the electrodes of the input transducer, as shown in FIG. 3. All six lateral faces form a closed surface, the length of which in the X-axis direction determines the period

the circulation of the acoustic wave (Fig. 3 shows a scan of the lateral surface of the hexagon corresponding to one period of circulation).

The delay delay works as follows.

The ultrasonic surface wave, emitted by the input transducer 9, propagates along the perimeter of the sound duct in the direction of the output transducers 10-

13. Between the input transducer 9 and the inclined face 7, the front of the ultrasonic wave is parallel to the electrodes of the input transducer (Fig. 4a).

After a single passage of the wave

sloping face 7 wave front acquires

a bias at a certain angle a (see Fig. 4c), the value of which is determined by the magnitude of the bevel angle (3 {Fig. 2). With each subsequent circulation, the skew of the wave front increases, taking the values 2a, 2a, ..: pa, where n is the number of circulation. The above property is illustrated in FIG. 4, where the position of the wave front is shown through a time multiple of the circulation period (positions a, b, c .... n).

Receiving transducers effectively work: they only work when their electrodes are parallel to the front of the incident wave. Due to this, each iriem converter turns out to be tuned only for a certain circulation period when the wave front and electrodes of the corresponding converter turn out to be collinear.

Thus, the delay of the signal at the output transducers depends on the angle of rotation of the pre-decoder and, consequently, on the number of circulations that the ultrasonic wave has to make before its front becomes collinear with the electrodes of this transducer. The number of circulation, in turn, depends on the bevel angle of face 7. Practically, the bevel angle is chosen based on the required delay. This angle does not exceed a fraction of a degree.

Subject invention

Line delay elastic surface wave by ed. St. No. 433623, characterized in that, in order to prolong the delay of the signal, the plane of one of the six lateral working faces of the single-crystal quartz sound duct is parallel to the crystallographic axis X and tilted to the axis Z.

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