This circuit was obtained from an 80's Radio Electronics. The circuit decodes “scrambled” or sinusoidal encoded signals by providing an audio signal at the output.
In this circuit, from a 1977 publication, we have the traditional version of a filter tuned to 1...
We find this circuit in an American 1980s documentation. Modern equivalent integrated circuits can be...
Found in an old Popular Electronics this circuit can also be adapted to be used as a shield. In...