We found this good amplifier in a Japanese publication of 1966. Transformers are uncommon nowadays and the power supply is included. Power is a few watts.
The operational amplifier is old. The circuit is from an 80's documentation but can be designed...
The connection of high-value input resistors causes the circuit to behave like a conventional...
We find this encoding circuit in an American 1980s amateur radio documentation. The circuit can be...