United States of America As Represented by the Secretary of the Air Force

Thomas L Szabo

Kenneth R Laker

Andrew J Slobodnik, Jr

Harold M Frost

Passband distortion due to mass loading in withdrawal weighted surface acoustic wave transducers is substantially reduced by a thinning technique in which interdigital transducer electrodes are selectively withdrawn to synthesize a response function H.sub.o '(N). H.sub.o '(N) is a modified response function that has been scaled from a desired response function H.sub.o (N) by a thinning factor THIN. THIN is a positive, non-zero constant with a maximum value of unity. Thinned withdrawal weighted transducers fabricated in accordance with the technique have electrode weights that are normalized to less than unity and achieve mass loading reduction with a minimum amount of degradation of the desired response function.

Thinned withdrawal weighted surface acoustic wave interdigital

A handheld, compact, self-contained transducer unit for electromagnetic generation and detection of ultrasound on or in metals and other media is realized by mounting short, flat cable sections directly on a small, powerful permanent magnet. The cable sections are interconnected in an electromagnetic transducer circuit configuration and the plane of the flat cable transducer circuit structure is perpendicular to the magnet magnetization axis. Fabrication of the device can be accomplished by selectively connecting the conductor ends of a flat strip electrical conductor segment and affixing the conductor segment to an appropriate surface of a samarium-cobalt permanent magnet.

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Boston, MA, United States of America

Thomas L Szabo