公开(公告)号：US3573673A

公开(公告)日：1971-04-06

申请号：US3573673D

申请日：1969-01-08

Applicant: ZENITH RADIO CORP

Inventor： VRIES ADRIAN J DE ,  DIAS FLEMING ,  WOJCIK THOMAS J

IPC: H03H9/00 ,  H03H9/02 ,  H03H9/64 ,  H03H9/20

CPC classification number: H03H9/0038 ,  H03H9/0042 ,  H03H9/02622 ,  H03H9/02685 ,  H03H9/02842 ,  H03H9/02866 ,  H03H9/02874 ,  H03H9/64

Abstract: A body of piezoelectric material is capable of propagating acoustic surface waves and a first transducing device is coupled to a surface of the body to develop those waves. Spaced on the same surface from that first device is a second transducing device. The spacing is sufficiently small that crosstalk exists between the devices. To reduce the magnitude of that crosstalk, one or more of several different decoupling arrangements are included. These comprise the connection of diametrically opposite transducer electrodes to a common plane of reference potential, the connection of the mutually closest electrodes of the respective transducers to a plane of common reference potential, the disposition of one or more ground electrodes between the transducers and across the path of wave propagation, the development across the transducers of signals balanced with respect to such a plane, the physical shielding of the space generally above one of the transducers, the inclusion of a conductive shield on the surface opposite the wave-propagating surface and the formation of shielding channels in that surface opposite the wave-propagating surface. In addition, the wave propagation path advantageously is caused to be oriented at an angle relative to the end surfaces of the piezoelectric body in order to minimize reflected wave interference.

公开(公告)号：US3581248A

公开(公告)日：1971-05-25

申请号：US3581248D

申请日：1969-03-26

Applicant: ZENITH RADIO CORP

Inventor： VRIES ADRIAN J DE ,  WOJCIK THOMAS J

IPC: H03H9/02 ,  H03H9/145 ,  H03H9/64 ,  H04R17/10 ,  H01V7/00

CPC classification number: H03H9/14597 ,  H03H9/02574 ,  H03H9/02622 ,  H03H9/02842

Abstract: A body of piezoelectric material propagates acoustic surface waves. Coupled to a surface of the body is a first transducer that launches the waves. Spaced on the same surface from the first device is a second transducer that responds to the launched waves. In order to reduce interference from reflections and increase efficiency, an end surface of the body is selectively located with respect to the adjacent transducer and is formed to define a particular angle with respect to the wave propagating surface. With the transducer elements in the form of interleaved combs of electrodes, absorption of reflections from an end surface is increased by effectively locating the end surface a precise fraction of an acoustic wavelength from the nearest comb electrode or tooth. Moreover, the response of the combined apparatus to signals being transmitted may be altered by changing either the angle that the end surface forms with respect to the propagating surface or by changing the spacing of the end surface from the transducer. The response also may be altered by depositing a different material on the wave propagating surface.