How does pulser-receiver circuit work

Question

I want to set up an experiment exactly as given in this data sheet for the T/R switch that I recently bought (the MD0101):

Every pulser receiver circuit that I’ve found neglects to address what happens during the “receive” portion of the event, i.e., if you’re using a function generator that just pulls the output to ground after sending out a pulse train, how are you supposed to be able to sense any movement in the piezo transducer if both of its plates are grounded?

The only way this circuit would work is if the function generator immediately disconnected its channel after sending out the pulse train, correct?

Answer 1

Close... The Tx must stop the ringing faster than the expected echo return time. This is due to stored energy.

Thus the sequence is stop Tx, short circuit device, then open high impedance and unblock Rx which was shorted during Tx.

I once had exactly the same problem with a tiny servo motor with position feedback. I moved with a half-bridge to pull up or down V+ or V- until position error was zero. When null error was detected, it floated but the tiny stored inertia caused a small offset error to jump at turn off. So on my SCADA design, I had to send a command to short circuit my half-bridge (activate both drivers) for <<1ms to stop the motor aggressively and short-cct both supplies by V/DCR to stop the inertia of the motor then open both drivers to detect external forces. Your time duration will be much less and depends on BW of the resonator. My solution worked like a charm yet I had never heard of it before.