Thinking some more about this over lunch, I had clearly forgotten
that in reducing the frequency by a factor of 10 you also reduce
the phase shift by 10. You therefore have to multiply the phase
shift by 10 first, presumably by extending the transition modulation
cycle
by 5. I think that this then makes the output invarient with respect to
the relative phase of the counter and the carrier.
It then occured to me that rather than amplitude modulating the
carrier to reduce the sidbands associated with the phase
transition, that you could reduce the rate of change of phase
and acheive the same effect at constant amplitude. Is that
correct?
73
Stewart G3YSX
Stewart Bryant wrote:
I was thinking some more about Jame's talk on Wolf yesterday,
and I have a few basic questions.
Wolf consists of a data encoding system layered over an
error recover system, layered over a bit synchronisation system
finally layered over bpsk. The upper layers woud work fine
over any transmission layer ie dfcw. Is BPSK actually the most
optimal bit transmission system?
Am I correct in thinking that BPSK is so good because you are
actually repeating the bit on every carrier cycle and integrating
the result?
I was also thinking that you could send wolf on the divide down
CW transmitters that some folks use. By injecting the audio
tone from a PC into a 13.6MHz transciever operating SSB and
then dividing down by 100 you should generate an equivelent
signal to the linear translation approach save for the envelope
shaping. However by keying the carrier off-on during the transition
the normal CW wave shaping should clean up the signal.
Does this work? Note that the error in the carrier will be the
dominant term, and not the error in the the modulation, which may
have some advantages.
Stewart G3YSX
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