Abstract: Provided is a sonar transmitter in which the structure is simplified and the power loss is decreased. A sonar transmitter comprises: a load unit having a transformer constituted with a primary wiring and a secondary wiring, and a wave transmitter to which the secondary voltage generated in the secondary wiring is applied; a control unit for outputting a PWM signal which originally has no offset voltage; and a transmission circuit unit which amplifies the PWM signal outputted from the control unit and applies it to the primary wiring as the primary voltage. The control unit comprises a memory circuit formed by ROM or RAM which stores a transmission signal waveform and a control circuit formed by a microcomputer or DSP, for example. With the present invention, a conventional feedback circuit, an adder and the like become unnecessary by outputting the PWM which originally contains no offset voltage.

Abstract: An arithmetic unit detects difference ? (=X?Y) between a sound source arrival azimuth X° of a sound wave, which is transmitted from a sound source buoy and is directly received in a wave receiving buoy, to a reference axis of the wave receiving buoy, and a target arrival azimuth Y° of a reflective sound, which is reflected by a target, to the reference axis of the wave receiving buoy. The arithmetic unit detects an azimuth angle ? of the sound source buoy on the basis of position information (latitude and longitude) of the sound source buoy and wave receiving buoy that is obtained by using GPS. Then, the arithmetic unit detects the azimuth (target azimuth) of the target to a magnetic north azimuth by the operation of (???).

Abstract: Provided is a sonar transmitter in which the structure is simplified and the power loss is decreased. A sonar transmitter comprises: a load unit having a transformer constituted with a primary wiring and a secondary wiring, and a wave transmitter to which the secondary voltage generated in the secondary wiring is applied; a control unit for outputting a PWM signal which originally has no offset voltage; and a transmission circuit unit which amplifies the PWM signal outputted from the control unit and applies it to the primary wiring as the primary voltage. The control unit comprises a memory circuit formed by ROM or RAM which stores a transmission signal waveform and a control circuit formed by a microcomputer or DSP, for example. With the present invention, a conventional feedback circuit, an adder and the like become unnecessary by outputting the PWM which originally contains no offset voltage.

Abstract: An arithmetic unit detects difference &agr; (=X−Y) between a sound source arrival azimuth X° of a sound wave, which is transmitted from a sound source buoy and is directly received in a wave receiving buoy, to a reference axis of the wave receiving buoy, and a target arrival azimuth Y° of a reflective sound, which is reflected by a target, to the reference axis of the wave receiving buoy. The arithmetic unit detects an azimuth angle &bgr; of the sound source buoy on the basis of position information (latitude and longitude) of the sound source buoy and wave receiving buoy that is obtained by using GPS. Then, the arithmetic unit detects the azimuth (target azimuth) of the target to a magnetic north azimuth by the operation of (&bgr;−&agr;).