This circuit from the 80's makes use of two transconductance operationals of the time. Modern equivalents can be used. The circuit does not need to be powered by a symmetrical source.
Found in a Maxim documentation from the 90s, this circuit produces a voltage of 5 V from an input...
Unlike the previous one, this circuit is intended for the reception of frequency modulated signals...
This circuit was obtained from Popular Electronics from March 1967. The transistor used is from...