| 摘要 |
PURPOSE:To reduce electric power consumption by performing transmission to remote places only for a specified period of time after the transmission of underwater searching pulses, and performing transmission to remote places when searching signals are obtained at a time other than the specified period of time. CONSTITUTION:A clock pulse generator 15 drives a frequency divider 14 together with a synchronizing code generator 23, a counter 32, and a shift register 33. The outputs of the divider 14 form a synchronizing wave (d), a switching wave (c), a distance gate wave (e) and transmission pulses P1, P2 according to various combinations. A transmitter 3 is switched to receivers 1, 2 at every T1, T2 by a select switch 4, and emits serarching signals P1, P2 alternately from above to below fish nets. P11, P12 are detected from the lower side with a receiver 5 and P21, P22 from the upper side. Said synchronizing gate wave (d), switching wave (c), and distance gate wave (e) are combined by logical circuits and only when the seraching signals are detected in the receiver 5 in constant periods T01, P02 and at times other than these, an electric power amplifier 10 is operated to transmit signals from the fish nets to a towboat. Thereby, the consumption of batteries is reduced. |
