| 摘要 |
1. A high resolution sound wave detecting system having a fan-shape beam of receiver sensitivity comprising a pair of transducers having elongated active faces coplanar and in end to end relation, an output signal channel for each transducer, means including two local oscillators of different frequencies connected to heterodyne against each other for producing timing pulses having a repetition rate equal to the frequency difference of said oscillators and individually against the output signals in the two transducer channels, means for mixing the beat frequencies of the heterodyned output signals and producing therefrom signal pulses having a repetition rate equal to the frequency difference of said oscillators, an output circuit, and means responsive to a signal pulse and a timing pulse coinciding in time for passing the signal pulse to the output circuit.
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