This circuit has a frequency range of 30 Hz to 100 kHz with an output signal of 1 Vrms. We found it in 70s American documentation. The integrated circuits are CA3140.
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,...