Patent ID: 6950372

Claim:
A digital sounder module comprising: a sonar transducer for transmitting an acoustic sonar wave at a selected frequency and pulse rate and for receiving echos of said transmitted acoustic sonar wave reflected from objects and for converting said received acoustic sonar wave into a first electrical signal; a band-pass filter for providing a first wide bandpass filtration on said first signal to produce a second signal; an amplifier for controlled amplification of said second signal to produce a third signal, said third signal being an amplified carrier wave; an analog to digital converter for receiving said amplified carrier wave, a rate at which said amplified carrier wave is converted to a digital signal by said analog to digital converter provides a harmonic sub-sampling, and said analog to digital converter transforms said amplified carrier wave into a digital intermediate frequency; a programmable logic device, said programmable logic device provides (i) a variable gain control signal to said amplifier for normalization of the amplitude of reflected echos within said second signal by increasing gain in proportion to the distance of said echo reflection source from said sonar transducer, and (ii) a harmonic sub-sampling rate, cosφ, to said analog to digital converter such that said reflected transmitted acoustic sonar wave is above the Nyquist frequency; and a microprocessor, said microprocessor provides an output for a display of said reflected echos.