[Elecraft] [K3} [KX3] SSBT like CWT ?

[Peter Lambert]

Hi Erik,

It's R & D.  Anything could happen.

I agree it's obvious but so are many things we see around us that weren't
there a short time ago.

The fundamental (vocal cord vibration frequency) changes constantly but not
particularly fast (it is a mechanical thing we do with our muscles).  The
constant is the original carrier frequency.  The relationship between the
vocal cord harmonics have a computable relationship back to the original,

I do think it's doable.   I've done some work on speech compression that
gives me some level of confidence.

Cheers,
Peter


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Erik Basilier
Sent: Tuesday, 5 February 2013 8:05 PM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] [K3} [KX3] SSBT like CWT ?

Peter, yes, I am sure many have thought about this. For something so
relatively obvious, one has to wonder why it hasn't already been done.
Perhaps the rapid changes in typical contest speech makes it hard to get an
accurate enough fix on the spectrum, unless one asks the other party to say
a long "aaaaaah" or some such sound? Or maybe the computing speed of the
hardware is a practical obstacle for a given rig? Maybe it has already been
tried by several people, and they ran into some kind of obstacle? Does the
frequency around 85 Hz stay very constant for a given speaker, as he or she
produces a variety of sounds? 

 

73,

Erik K7TV

===============================================

This is an algorithm I've contemplated writing many times.

 

Voice results from the vocal cords snapping together in the range around
85Hz.  The filter effect of the various cavities, throat, mouth and nasal
are quite high Q and filter the harmonic rich vocal chord excitation to
produce the voice.

 

If you watch an SSB signal on your PSK waterfall you'll clearly see the
harmonics of the vocal chords.

 

I think a DSP algorithm that calculates the location of the carrier based on
the separation between the vocal chords is a definite doable proposition.

 

It would give SSB the perfect clarity you seek.

 

Love to have a go at this (I do DSP).  Do you Elecraft guys want to have a
go or interested in using it if I do it ? (I could probably do it as a piece
of PC code that processes sound card input so you could evaluate it).

Doesn't feel like to be a difficult thing to do.

 

Cheers,

Peter VK4JD

 

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