SU540354A1 - Delay line on elastic surface waves - Google Patents

Description

one

The invention relates to ultrasonic delay lines and can be used in various radio devices to delay radio signals.

The known delay line on the elastic surface waves, consisting of a single-crystal quartz sound duct with rounded edges of the working faces, oriented along the Z axis, the input and output interdigital transducers located on the working face x 1.

However, in the known delay line, there is an increase in internal losses with increasing angle of turn of the electrodes of the interdigital transducers with respect to the Z axis.

The purpose of the invention is to reduce internal losses.

To do this, in the Proposed delay line on elastic surface waves, the transducer electrodes are parallel to the Z axis, and some of the working faces are oriented along the 4-X and -X planes, with the lengths of the sound-beam trajectories in the + X and -X planes different.

FIG. 1 shows several embodiments of the proposed delay line on elastic surface waves, a general view; in fig. 2 - orientation of the working faces of the quartz chute; in fig. 3 is an exemplary view of the trajectory of the ultrasonic beam

on the scans of the working faces of the quartz acoustic duct with their orientation in accordance with FIG. 2

The delay line on elastic surface waves contains a single-crystal quartz acoustic duct 1, made, for example, in the form of six-, four- or trihedron (Fig. 1 a, b, c, respectively), with rounded edges of working faces A, B, C, D, D (Fig. 1 a), E, F, 3, K (Fig. 16), L, M, H (Fig. 1 c), oriented along the Z axis, input 2 and output 3 interdigital transducers located on Workers grand h x. In all possible configurations of the proposed delay line on elastic surface waves, the electrodes of the interdigital transducers 2 and 3 are parallel to the Z axis, and some of the working faces are oriented along the planes m + X and -X, with the lengths of the sound paths in the x + X and X are different. The radius of rounding of the edges of the working faces is chosen from the condition R (5- -6) Jaakust, where KuKycf is the length of the elastic surface wave corresponding to the lowest frequency bandwidth limit. The input 2 and output 3 interdigital transducers can be located on any of the working faces of the single-crystal quartz sound duct 1. Placing them on the working faces of the X-cut allows

get slightly smaller internal losses due to the greater efficiency of this cut.

The delay line on the elastic surface waves works as follows.

An electrical signal applied to the input interdigital transducer 2 excites an elastic surface wave propagating around the perimeter of the quartz sound duct due to the presence of rounded edges. The phase front of an elastic surface wave throughout the propagation path remains parallel to the Z axis (in the absence of a significant beam divergence).

The energy flow of the elastic surface wave on the working faces oriented along the planes m + X and -X (see Fig. 2 a, b, c), propagates in the direction of the wave normal (right in Fig. 3a), and the working face perpendicular to the X axis deviates from the wave normal by angle 6. Due to the displacement of the energy flow on this working face, the elastic surface wave trajectory becomes helical with a step determined by the length of this working face.

An exemplary view of the sound beam trajectory for the proposed delay line in the embodiments of FIG. 1 a, b, c is represented on scans of the lateral surfaces of the quartz sound duct, respectively, in FIG. 3 a.

b, c. Placing the output transducer 3 so that the sound beam intersects it at the desired turn, you can implement the desired delay. To reduce the level of false

signals it is necessary that the pitch of the helical path of the elastic surface wave be larger than the transducer aperture at the receiving point. The delay line, thus designed, has low internal losses.

Claims (1)

Invention Formula Delay lines on elastic surface waves, consisting of a single-crystal quartz sound duct with rounded edges of the working faces, oriented along the Z axis, the input and output opposite-end transducers located on working faces, characterized in that, in order to reduce internal losses, the transducer electrodes are parallel to the Z axis, and some of the working faces are oriented along the planes and -X, and the lengths of the trajectories of the sound beam in the planes x + X and -X are different. The source of information taken into account in the examination: 1. Auth. St. USSR № 433623, M. Kl. N OZN 9/30, 29.12.71 (prototype). Rig. one Uig 2 -, A 6 in g m; A 6 B f m . W7 3K / Ll m