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.
The coil consists of 100 turns of wire 28 in a wooden or PVC tube from 2 cm to 2.5 cm in diameter with...
This circuit is based on the Texas Instruments LMC662 and has the function of monitoring the audio...
This circuit, which uses only common transistors, was obtained from a 1988 publication, but can be...