This circuit was found in an 80's Electronic Engineering. The power supply must be symmetrical. The no value components are calculated for the desired frequency.
This circuit for PC and which can also be used with microcontrollers was found in an English...
This two-tone decoder has a bandwidth of 24%. The circuit is from a 1994 Electronics Now. The...
The LMV321 is a low voltage operational amplifier from ON Semiconductor. The following diagram,...