This is the receiver circuit for the transmitter of the previous circuit using an integrated circuit of the time. The circuit is in the same Radio Electronics magazine as August 1986.
This circuit was obtained from an American 80's documentation. The balanced mixer can be shown in...
This circuit was found in a 90s Electronic Engineering. The quadruple operational amplifier can be...
I found this circuit in an English publication from 1989. This configuration can be mounted with...