This circuit is from an old Signetics documentation. It can be implemented with modern operational amplifiers. The power supply must be symmetrical.
This is the receiver for the previous transmitter, also using a transducer not very common in our...
Here we have a transceiver for the amateur radio range, which operates in the 40 m band (7 MHz),...
The integrated circuit used in this circuit is not very common, but an equivalent one can be...