| 摘要 |
A cart-mounted acoustic transmitter and receiver system for echo-locating underground structures, such as piping. A transmitting transducer, mounted in a non-resonant tube and positioned adjacent to the ground, directs sound waves downwardly through an air column while a receiving transducer, rolling over the ground, picks up echoes returned from buried objects. The rolling transducer includes a piezo-electric transducer mounted in a tubular plastic axle on which an elastomeric disc rotates making contact with the ground. A pair of port and starboard rolling transducers provide inputs to a differential amplifier to enhance detection by increasing discrimination against the return from the benign land mass.
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