| 摘要 |
PURPOSE:To form a receiving beam successively in different directions, and to catch and display a signal returning from the directions by emitting a detecting pulse in the direction of a wide range, receiving a returning signal so as to deviate the frequency of a reflected wave, and pulse-compressing the receiving signal. CONSTITUTION:A transmitter 1 emits a detecting pulse in the direction of a wide range at a constant period. A receiving means 2 is constituted of an ultrasonic vibrator 21 which executes a uniform circular motion and has a directional pattern, and supplies a receiving signal to one input terminal of a multiplier 3 and 4. A signal of a constant frequency coming from the same sound source is received by deviating the frequency by a Doppler effect. A signal generator 5 generates a cosine wave and a sine wave, a filter 6 and 7 fetch a specified frequency signal from in an input signal, and a matched filter 8 and 9 compress the pulse width of a receiving signal. The output signal of an adder 10 contains a reflected signal returning from the direction directed by the formed receiving beam and is supplied to an indicator 11. In this way, wide range underwater detection and display can be executed by suppressing a width beam is formed. |
