We find this encoding circuit in an American 1980s amateur radio documentation. The circuit can be implemented with equivalent modern components.
Originally created to feed the filaments of a 12AX7 as an audio preamplifier to eliminate the...
The BFO or Beat Frequency Oscillator is used to receive telegraphic signals or even modulated in...
This circuit is a variation of the previous one, containing a modulation input. The components are the same....