Strictly, CW is a three symbol code with source coding (variable length alphabet, like varicode) with soft decision coding, and mild FEC (operators interpretation of the code based on S/N) and some convolutional coding with soft decisions (matching characters received against patterns / words.
Once you start using soft decision decoding, error correction and mult- bit-per-symbol waveforms, it becomes a bit difficult to really call anything a digital modulation at all. Especially when analogue processing is mostly performed digitally now, anyway Andy www.g4jnt.com
