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

Tue Feb 5 01:09:54 EST 2013

That's it precisely.  Should be able to resolve the exact frequency and
phase of the carrier.  There's a lot of information there to work with (take
a look at that waterfall with SSB you'll see what I mean).  Given the
carrier is rock stable with time it should be possible to do this with VERY
good accuracy.  I don't think it'd be all that hard at all.

Not a lot of point doing this on your own unless you've got an open source
rig.  I don't.  I've got Icom and Elecraft.  Reckon it could be done and
tested in the PC via a soundcard.  I'd be more than interested in doing it
if Elecraft were at all interested (even in an evaluation).  It'd feel like
a contribution to the amateur pool, I'd love to bring a little of my work
into the hobby.  There's probably plenty of DSP guys like me on this list
that could do it.

I tune for the "natural" sound that prompted Erik to write his original
post.  It feels a bit like getting all the lows to "line up" but when you do
find the spot it's sweet.  If you're in a particularly anal mood it can be a
challenge.  It's this that has made me contemplate the possibility many
times.

73's Peter  VK4JD

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Wright, Robert
Sent: Tuesday, 5 February 2013 3:54 PM
To: Elecraft at mailman.qth.net
Subject: Re: [Elecraft] [K3} [KX3] SSBT like CWT ?

This sounds like an interesting project.  It would seem that the technique
would be finding the offset frequency that provides the best alignment of
harmonics, which is what we naturally do by ear.  Not difficult, but would
probably need a bit of tweaking to provide good real-time performance.   It
would only be valuable if it was significantly faster than what we do
manually.

It's good when projects are self-motivating.

73, Bob, N7ZO

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Peter Lambert
Sent: Monday, February 04, 2013 9:25 PM
To: 'Erik Basilier'; Elecraft at mailman.qth.net
Subject: Re: [Elecraft] [K3} [KX3] SSBT like CWT ?

You are spot on, Eric

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

-----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 3:07 PM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] [K3} [KX3] SSBT like CWT ?

At Field Day I have observed a number of operators operating SSB. I have
noticed that there is a great variation in skill when it comes to tuning the
RX to an SSB signal. Sometimes I feel that the op has it tuned all wrong and
I almost want to grab the knob. Maybe different people's brains focus on
different aspects of the sound when they tune the RX. Some people seem to
want to tune for the best balance between highs and lows, when the HI CUT
and LO CUT would do a better job. When I tune the RX, I believe that I am
not trying to balance highs and lows, but rather trying to find some kind of
harmony in the sound. If I were tuning in a piece of music from an AM BC
station with the radio in SSB mode, clearly the harmonics of a musical note
will not be harmonious if the radio tuning is off. If a voice is used for
singing, it is like a musical instrument. If the voice is speaking, I
believe the harmonics are still at play as with a musical note. This leads
me to speculate that it
  would be possible to run an FFT on the received audio and determine by how
much the RX tuning is off, just like with CWT. I am very fond of the CWT
feature on the K3 and on the KX3. I wonder if it would be practical to add
SSBT as a new feature.

73,

Erik K7TV

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