| 摘要 |
PURPOSE:To measure the positions of plural targets which are present on a concentric sphere having its center at a transmitter-receiver by using >=2 transponders which respond to a sent signal from the transducer at different frequencies. CONSTITUTION:The pulse-modulated signal of frequency f0 generated by a transmitter 1 is sent to the transducer 3 through a transmission/reception switching circuit 2 and converted into an ultrasonic wave, which is radiated into water. This ultrasonic wave signal is received by the transponders 4 and 5 installed underwater. The transponders 4 and 5 respond to this received signal and send ultrasonic pulse-modulated wave signals of frequencies f1 and f2. Those signals of the frequencdies f1 and f2 are received by the transmitter-receiver 3. The ultrasonic wave signals of the frequencies f0, f1 and f2 area reflected bt a target 10 and all converted by the transducer 3 into electric signals, which are sent to receiving circuits 6, 7, and 8. The recovering circuits 6, 7, and 8 select the frequencies f0, f1 and f2 by BPFs 101, 102, and 103 and they are sent to an arithmetic circuit 9 after amplification 104 and detection 105 to compute the position of the target.
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