Azimuth adaptive phased array sonar

Claim 1

An azimuth adaptive phased array sonar (see FIG. 3), comprising a sensor (4) having an array of a plurality of ultrasonic transducer elements (4) which transmit ultrasonic signals and receive echo signals; a first delay stage (2a) which in accordance with a trigger signal supplied from a trigger generator (2) generates a plurality of driving signals having a phase relationship corresponding to the direction of transmission of the ultrasonic beams, respectively; a pulser (3) for amplifying the driving signals to produce output signals which drive said individual ultrasonic elements (4); an amplifier (5) for amplifying the echo signals detected by said individual ultrasonic transducer elements (4), respectively; a second delay stage (2b) for delaying the respective output signals of said amplifier (5) for achieving a phase relationship corresponding to the direction of reception of the echo signal; control means (7) for controlling the phase relationship in said first delay stage (2a) and said second delay stage (2b) in accordance with the respective direction of transmission of the ultrasonic signals and directions of reception of the echo signals; a bandpass filter (6) disposed in a signal path of received echo signals and/or in a signal path of producing ultrasonic signals, said bandpass filter (6) having a variable frequency response; and wherein said control means (7) further controls said bandpass filter (6) so as to substantially shift the pass band toward a lower frequency side as the azimuth of the ultrasonic beam is increased.