Found in old documentation, this circuit uses a double gate MOSFET. The operating frequencies depend on the coil, and the indicator is a microammeter.
This is the simulation of a Ultrasound Receiver using the 741 IC, an operational amplifier....
The resonant circuit depends on the crystal frequency that can go up to a few megahertz. The...
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...