PURPOSE: To facilitate a wireless communication between divers each other or between a diver and a person on a ship by outputting a voice corresponding to a switch input from a voice synthesizing circuit previously storing the voice, transmitting the signal as an ultrasonic signal after analog modulation and demodulating so as to output a sound signal in a reception side.
CONSTITUTION: By operating a switch, a corresponding code is outputted from an encoder circuit 2 to a voice synthesizing output circuit 3. The speech synthesizing output circuit 3 reads out corresponding voice data which is previously recorded from a ROM and D/A converts it to transmit to a modulation circuit 4 as an analog sound output. The signal is modulated, for example in terms of AM modulation, in the modulation circuit 4 and amplified in a power amplifier 5, so that the ultrasonic signal is radiated from an ultrasonic transducer 7 into the water through a circulator 6 as analog sound data. The reception part inputs the signal in a pre-amplifier part 8 through the circulator 6 and amplifies it. After the signal is detected in a demodulation circuit 9, it is amplified in the power amplifier 10, so that a diver can hear the signal by using a bone conduction earphone 11.
SUZUKI MASAMITSU
KADOKAWA YUICHI
