If the driving source is a voltage, current limited by a series resistor, maybe 50R, with controlled rise and fall times during the "0" gain portions, then the ESL and op-amps slew rate effects will be greatly reduced. Let's say 100KHz, 5V with 1.5uS rise and fall times. Now do your 1,0,-1,0 trick, add gain and filtering and feed to ADC. Sounds like a 800KHz osc divided by a flip flop to 400KHz and both FF outputs divided to 100KHz to get the driving and demodulating signals. Harry