Message-ID: <3B090CF7.A47462CC@virgin.net>
Date: Mon, 21 May 2001 13:41:27 +0100
From: "Stewart Bryant" <stewart.bryant@virgin.net>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Wimborne talk on Wolf
References: <E14zzGa-0006Y1-00@gemini.herts.ac.uk> <3B08FCDC.484F74DF@virgin.net>
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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