Trevor Smithers wrote:
What you really need is a method of identifying the actual ssb speech waveform, extracting the noise
from it leaving the signal in the clear. There is a company in Germany that produces an outboard unit
that I find very effective without the degradation in the audio. Audio demo here
http://www.home.vrweb.de/michels/sound_demo.htm
The web site isn't exactly forthcoming about how it really works, even
though they claim to have a patent (personally I think patents go
against the spirit of ham radio). Lingua suggests a voice tract model,
but the talk of envelopes doesn't seem consistent with that.
Incidentally, MP3 is not a good format for representing noisy signals.
The compression algorithm assumes that the signal has strong spectral
peaks which greatly exceed the noise. It actually suppresses parts of
the spectrum, where it thinks the sound is dominated by adjacent
spectral peaks.
In general, noisy signals are difficult to compress. Sound will show a
bias towards zero, so will be partially comprssible.
--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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