| 摘要 |
PURPOSE:To prevent the consumption of a specified pen, and to extend a life of the whole device by setting irregularly a delay time of a delaying circuit by a random number generating circuit. CONSTITUTION:A recording device is provided with a delaying circuit 20 and a random number generating circuit 21 for setting a delay time. When a power source is turned on, a controlling circuit 1 is operated, a switch 22 is turned on and the circuit 21 is operated. Also, by the operation of the circuit 1, an ultrasonic signal is emitted into the water from a transmitter-receiver 4 through a transmitter 2, and a transmission/reception switching device 3, reaches the sea bottom 11 are reflected, received by the transmitter-receiver 4 and converted to an electric signal, and thereafter, applied to the circuit 20 through the switching device 3, a receiver 5, and a recording amplifier 6. A delay time is determined by a random number which has been generated from the circuit 21, and the circuit 20 delays an output of the amplifier 6 by its delay time, and gives its output to a pen 8 which has been selected by an analog switch 7. In this way, by the circuit 1, the switch 7 switches successively the pin 8 from a pen 8-1 of the left end side to the direction of a pen 8-n of the right end side, therefore, by the pen 8 which has been switched within the delay time, a signal of the time point of transmission is recorded.
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