| 摘要 |
This invention relates to a meter for indicating the depth of water. More particularly, the invention provides a depth meter having a transducer means for imparting sound pulses near the surface of a body of water in response to electrical energization and in turn for providing electrical signal output in response to reflected sound pulses, a time base circuit providing evenly spaced systems initiating signals, an oscillator circuit providing sequential bursts of electrical energy to the transducer, in response to the system initiating signals, a receiving amplifier connected to the transducer amplifying the reflected signal output in response to reflected sound waves, a metering circuit connected to the time base circuit and the amplifier providing means of indicating the time response between the transmitted signal and the signal received in response to receipt of sound waves as an indication of the distance to the bottom of the body of water reflecting the sound waves from the transducer and a time varying gain control circuit connected to the time base circuit and receiver amplifier providing a time varying bias to the amplifier following each system initiating signal, the bias being applied to the amplifier with time whereby signals resulting from the bottom at greater distances from the transducer are amplified more than signals resulting from shallower depths.
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