Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power supply must be symmetrical. The circuit can be implemented with modern operational amplifiers.
This circuit, from the SGS manual of linear integrated circuits of 1982, uses the muting input to...
This audio configuration of televisions from the 1960s was found in a Mullard transistor reference...
This long delay circuit was found in the July 1973 Radio Electronics magazine. The capacitor...