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.
Of course, the range of this transmitter found in a 1992 documentation is not exactly 4 km, as it...
This version of triac control is from a 1968 documentation. The circuit uses components from the...
This circuit was found in the July 1978 issue of Radio Electronics magazine. The circuit uses a...