This circuit makes use of a specific 80's component and was found in an American manual of the time. A matrix keyboard allows you to select one of several music programs.
An excellent signal generator for the audio track was found in a 1983 documentation. Its complete...
CMOS inverters can be used as amplifiers, obtaining a flat response up to approximately 20 kHz....
This circuit uses BCD switches to program the frequency to be divided. The circuit is from a Radio...