Furuno Electric Company Limited

Akira Sugiyama

Kiyomi Minohara

Hideharu Morimatsu

Masajiro Iida

Hiroshi Nakai

Yuzo Kobayashi

An ultrasonic detection system having an array of ultrasonic transducers that are uniformly closely disposed relative to each other such that the active surfaces for transmission or reception are maintained on a straight or curved line. The transducers form radiation or reception beams in a specific direction. Beam orientation is accomplished by selecting a group of transducers from the array and/or respectively applying appropriate phase-shifts to the signals to be fed to each of the transducers or to the signals produced from each of the transducers. Shields are maintained between two adjacent transducers for suppression of sidelobes.

Ultrasonic detection system

Scanning angle control for a linear array of spaced transducers in a pulse echo receiver is implemented by mixing the respective transducer outputs with progressively shifted output signals from a multi-stage, variable phase shifter fed by a local oscillator. The additively combined mixer outputs thus contain frequency sum and difference components, which are extracted by low or high pass filters to implement scanning control on either side of a perpendicular to the array. When a two dimensional array of transducers arranged in a row and column coordinate grid is employed, scanning in both azimuth and elevation may be implemented by coupling each column of transducer mixers to the respective phase shifter stages through digital delay circuits arranged in rows and fed by a variable frequency clock pulse generator, whereby progressive delays are provided in the columnar direction.

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Ashiya, Japan

Akira Sugiyama