On Sun, 21 Sep 2008 20:42:27 -0400, Joe Subich, W4TV wrote:
I think is it safe to treat the audio as band limited
That's like saying a driver is slow. How slow? Bandwidth limiting
CHANGES the complex impulse response of the system. It does not make
it not matter, or benign, just DIFFERENT.
On Sun, 21 Sep 2008 09:11:22 -0400, Paul Christensen wrote:
the square-wave impulse response
of the transformer becomes less meaningful.
As long as there is impulse noise, the square wave response of the
line out transformer is definitely relevant! As the folks at
Elecraft have noted, the
Have you considered the difference between hitting a transformer with a
fast rise / fast fall square wave and hitting it with one that is
narrowly band limited?
Ignoring for the moment the difference in filter shape between Gaussian
and the complex shape of the K3 crystal and DSP filters,
On Sun, 21 Sep 2008 13:31:00 -0400, Jack Smith wrote:
Have you considered the difference between hitting a transformer with a
fast rise / fast fall square wave and hitting it with one that is
narrowly band limited?
That's one of the virtues of my measurement method -- it looks at the
That's why I question the applicability of a ringing test with a square
wave having a rise/fall time measured in nanoseconds, as the audio that
makes it through the K3's crystal and DSP will not remotely resemble that
waveform.
Agreed Jack, if the DSP and/or AF stages truly limit impulses
: Elecraft List
Subject: Re: [Elecraft] K3 related - non-linear audio
transformer behavior
That's why I question the applicability of a ringing test with a
square
wave having a rise/fall time measured in nanoseconds, as
the audio that
makes it through the K3's crystal and DSP
Jack:
With regard to the plots under Comparisons and Conclusions, and also under
Frequency Response Compared, is it possible to change the source Z from
600-ohms to 50-ohms and re-test?
It would be an interesting exercise to see if THD (at ~ 1V RMS) and the
high-end frequency response of
Paul:
I've revised my non-linear transformer page in two respects:
1. Added the plot you requested. (Almost at the bottom of the page)
2. Added square wave ringing data for four transformers, although I am
not at all convinced that square wave ringing is an appropriate figure
of merit for a
Jack,
Thanks for the research - very interesting and it looks like a simple fix to
improve the performance of the K3 significantly. You've got me wondering now
though about DATA-A modes. As the K3 uses the same transformer for line in
your work suggests that the transmit performance will be
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