This circuit was found in an American 1980s documentation. The transistorized step is the receiver's last IF and the diode is the receiver's existing detector.
This voice scrambler circuit was obtained from an American 1990s documentation. Used operational...
August 2016 - The new Schottky diodes from Vishay's ESMP series for surface mounting can now be...
September 2017 - Texas Instruments PCM186x and PCM186x-Q1 Audio ADCs can be found at Mouser...