This circuit was found in a Motorola documentation from 1975. Modern equivalent transistors such as the BF245 can be used. The circuit is powered by 9 V voltage from cells or batteries.
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...