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.
We found this test circuit in Radio Electronics magazine from July 1962. The circuit uses...
We found this circuit in an American publication from the 1980s. Equivalent modern operational amplifiers...
The transistors in this circuit can be the BC548. Capacitors determine the frequency and can be...