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I want to communicate simple requests and ids over ultrasound.

To do this I need to modulate a message onto a 40kHz carrier to drive a ultrasound transducer.

Here you can find a simulation of what I am trying with a gilbert cell for modulation a difference amplifier as a driver for the transducer (not shown in the simulation) and an OOK demodulator consisting of a LP, an average detector and a comparator.

  • Is the difference amplifier (with +-50V as supply) sufficient as a driver for the transducer and can I also use it for the other end to amplify the received signal ?
  • If it is sufficient which HiV op amp would you recommend ?
  • Do you see any other design flaws ?
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    \$\begingroup\$ You might consider adapting a ranging circuit. And use FSK, not OOK. \$\endgroup\$
    – Chris Stratton
    Commented Sep 11, 2020 at 11:57
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    \$\begingroup\$ Depending on what you want to transmit, you might hack IR remote circuits. They use a 38 kHz carrier ... pretty sure they inherited that from ultrasonic remotes in the 1970s before IR LEDs and photodiodes became available. \$\endgroup\$
    – user16324
    Commented Sep 11, 2020 at 12:05

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It is hard to understand what is the output there on your simulation, kind a weird circuit. If the output is square pulse, you don't need an opamp, just two transistors like D-class amplifier. Such HV opamps do exist, also with DC/DC converters on board. Look for Apex HV opamp board. They also make PWM amplifiers.

You could also DIY it from discrete components, but I do think you need something that works out of box with good documentation.

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