| 摘要 |
A water depth digitizer produces a digital readout from a depth sounder of the type which produces an acoustic ranging pulse and which includes a transducer producing a receive signal representing the return of a reflected acoustic ranging pulse. A digital counter is started in response to an acoustic ranging pulse and is stopped in response to the receive signal occurring after the selected ranging pulse. In order to prevent erroneous readings which occur because the reflected acoustic ranging pulse is not of sufficient amplitude to be detected, a circuit is provided to detect valid information. The digital counter is reset when a receive signal is not received before the next occurring acoustic ranging pulse.
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