The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 21, 1978
Filed:
Apr. 25, 1977
James C Sethares, Burlington, MA (US);
Harold M Frost, Rockville, MD (US);
Abstract
Extremely sensitive velocity and position measurements are achieved with a surface acoustic wave (SAW) resonator device. A surface acoustic standing wave field is established on a movable SAW propagation surface by means of induced SAW pulses traveling on the propagation surface and their reflection from a SAW reflecting mechanism. Movement of the propagation surface causes periodic variations in the standing wave field amplitude. The frequency of the standing wave field amplitude variation is directly related to the SAW propagation surface velocity and its phase (i.e., total number of standing wave field amplitude variations from a reference point) indicates the SAW propagation surface position or how far it has moved from the reference point. One implementation comprises a rotatable aluminum cylinder on the surface of which SAWs are launched and detected by proximate but non-contacting transmitting and receiving electromagnetic transducers (EMTs). The reflecting mechanism used to initiate the standing wave results from the proximity of the EMTs and the coupling effect of the EMT magnetic fields. Frequency and phase information is extracted from the receiving transducer output by visually (CRT) or electronically counting standing wave amplitude variation cycles. Other implementation includes translatory planar SAW propagating surfaces and various transducer configurations and arrangements.