The operational amplifier used in this circuit is uncommon nowadays. We obtained this circuit from documentation from the 1980s, but it can be adapted to use more modern equivalents.
This is the receiver circuit for the previous remote control published in the same Radio...
This circuit, for signals up to 1 MHz, is based on an RCA operational amplifier. The circuit was...
This frequency shift modulation circuit was found in the November 1994 issue of Electronics Now...