[Elecraft] Technical question on keying of an SDR radio

[Phil Hystad]

If you look at various old circuit diagrams of ancient radios made from electronic circuits you find that the telegraph keying for the radio involves switching on and off the driving oscillator frequency or something similar.

However, with an SDR, you have other options and I have no idea how it is typically done.  For example, a digital signal can be produced that represents the Morse coding and this signal need merely be converted to analog and amplified.  Or, is there still an analog circuit being switched on and off for Morse code (telegraphy) keying with a modern SDR.

Can someone describe how this is done in a radio like the KX2.  And, is it done differently in the different Elecraft radios — I presume that the K2 would have the more traditional sort of circuit but that is really just a wild guess on my part.

73, phil, K7PEH