Hi, sorry for the lack of details. It's my first post on here!
OK, transmission medium is water (so assume 1500ms speed) transmission and reception transducer is piezo-electric. TX pulse is generated from Centre tapped transformer, push pull style. Square waves drive the fets, which when coupled to the highly capacitive transducer result in a modest envelope signal.
Distance measurement is variable from 1mtr, to approx 1000mtr. Hence the intended 75khz sampling interval, which should allow a sample of the signal every 1cm, so intended resolution of 5-10cm.
Adc resolution at 16bits would be more than enough I would think?
Thanks,
Brett