Using a 4046 PLL we found this circuit in the December 1989 issue of Radio Electronics magazine. The circuit operates at 220kHz, but this frequency can be changed by changing C3.
This circuit is from a 1974 Ferranti transistor manual. The circuit is analog, and the components used...
We found this circuit in the June 1987 issue of Radio Electronics magazine. With it, it is...
This circuit was found in a Hands On Electronics from the 90s. The microphone is a small 75-ohm...