Beautiful Design
Use an Opto isoloator and isolated power supply for VCO audio for preventng coil spikes feeding into opamps by inputting the final stage of the opamp after LM318 into optoisolator, then VCO circuit follows.
Other Beautiful Design by me
Also can we use a Rx coil..... and separate the Tx Rx sections electrically,use a separate power supply for Rx Opamps so that, voltage drop/spike at Tx during switch-on-off is eliminated which would affect the opamps, an opto isolator is used and triggered after Tx switch-off after a delay of <10usec and Rx OpAmp is activated and Rx signal is fed to opamps, and we can even minimize the delay to 2usec instead of 10usec after the Tx-on pulse width.
Find the signal level in the Rx after we switchoff the Tx coil, use a rx coil of few turns concentric with Tx. If the Rx signal levels are fine for amplification without noise then proceed with LM6624/22/26 Opamps for low noise specially for this design.
Use an Opto isoloator and isolated power supply for VCO audio for preventng coil spikes feeding into opamps by inputting the final stage of the opamp after LM318 into optoisolator, then VCO circuit follows.
Other Beautiful Design by me
Also can we use a Rx coil..... and separate the Tx Rx sections electrically,use a separate power supply for Rx Opamps so that, voltage drop/spike at Tx during switch-on-off is eliminated which would affect the opamps, an opto isolator is used and triggered after Tx switch-off after a delay of <10usec and Rx OpAmp is activated and Rx signal is fed to opamps, and we can even minimize the delay to 2usec instead of 10usec after the Tx-on pulse width.
Find the signal level in the Rx after we switchoff the Tx coil, use a rx coil of few turns concentric with Tx. If the Rx signal levels are fine for amplification without noise then proceed with LM6624/22/26 Opamps for low noise specially for this design.