| 摘要 |
A sonar transmitter comprises a load unit 70 having a transformer 73 constituted with a primary wiring 71 and a secondary wiring 72, and a wave transmitter 74 to which the secondary voltage generated in the secondary wiring is applied. A control unit 20 outputs a PWM (Pulse Width Modulated) signal which originally has no offset voltage, and a transmission circuit unit 90 amplifies the PWM signal outputted from the control unit 20 and applies it to the primary wiring 71 as the primary voltage. The control unit 20 comprises a memory circuit 21 formed by ROM or RAM which stores a transmission signal waveform, and a control circuit 22 formed by a microcomputer or DSP, for example. A feedback circuit, an adder and the like (see fig 1) become unnecessary by outputting a PWM signal that contains no offset voltage. This simplifies the structure of the transmitter and the power loss is decreased. |
