This space mark demodulator for FSK signals was found in an American telecommunication documentation from the 1980s. The circuit operates with 2025 Hz and 225 Hz mark space signals.
Although the author of this circuit indicates a power that he does not really have, considerable...
This circuit aims to digitally control several audio channels. The circuit is from American...
This circuit immobilizes a car with an old ignition system with platinum switches. It was found in the...