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.
Found in American documentation from the 1990s, this simple circuit excites a LASER diode. The...
This circuit was found in an old American documentation. The integrated circuit used is uncommon...
This circuit was obtained from the February 1990 issue of Radio Electronics magazine. The circuit...