| 摘要 |
PURPOSE:To prevent large electric power from being supplied by mistake when an ultrasonic wave transmitter is in the air by controlling the electric power supply from a transmitter to the ultrasonic wave transmitter so that the ultrasonic wave transmitter is supplied with electric power only when in the water. CONSTITUTION:The signal of the transmitter 1 is passed through a gate circuit 12, power-amplified by a power amplifier circuit 13, and applied as large electric power to the ultrasonic wave transmitter 21, which radiates an ultrasonic wave into the water. The transmitter 21 is provided with an underwater sensor 22 and outputs different signals according to whether the transmitter 21 is the water or air. A detecting circuit 14 discriminates the signal from the sensor 32 to close the gate circuit 12 when the transmitter is in the water and open the gate circuit when it is in the air. Consequently, the transmitter 21 in the air is prevented from being supplied with the large electric power to break down. |
