In theory, I believe that some of the sound card analysis programs can work,
but I'm not sure if they sample fast enough to detect
the change in pitch...although we're probably speaking of less than 50-100 mS
for detecting the duration of a "microchirp." Seems
like any PC should be fast enough, but I just don't know if enough will be
captured to the screen. The PSK31 "waterfall" displays
look like the trick because a pitch shift should be seen by a horizontally
shifted waterfall line. However, I haven't seen anything
out there that will give accurate results in a small enough pitch shift window
like 10-50 Hz.
I use a Fast Fourier Transform (FFT) program called SpectraPlus for my Hi-Fi
SSB work. The resolution down at the low end of the
audio spectrum is good but the FFT sample size at low frequencies must be very
large in order to offer enough resolution to see
small pitch changes. On the high end of the audio spectrum, the FFT size can
be made smaller, but then resolution is lost because
of the display's semi-log scale. I may experiment with it this weekend.
-Paul, W9AC
----- Original Message -----
From: <n4lq@iglou.com>
To: "A-USA,ex3" <al_lorona@agilent.com>; "'Paul Christensen'"
<paulc@mediaone.net>; "Ten Tec" <tentec@contesting.com>
Sent: Friday, February 01, 2002 2:20 PM
Subject: RE: [TenTec] RE: More About Clix
> Send one up here to Ky. I found a preowned one for $39,000 but would
> rather keep the house. Can a sound card keep up with this? Could one of
> the audio analyzer programs display the frequency change on the
> horizontal axis if it could only sample one dit? I would think the
> microchirp would only amount to one cycle or so.
>
> -----Original Message-----
> From: "LORONA,AL (A-USA,ex3)" <al_lorona@agilent.com>
> To: "'Paul Christensen'" <paulc@mediaone.net>, Ten Tec
> <tentec@contesting.com>
To: <tentec@contesting.com>
> Date: Fri, 1 Feb 2002 12:02:52 -0700
> Subject: RE: [TenTec] RE: More About Clix
>
> >
> > Paul--
> >
> > Man, you are absolutely right. I really just wanted people to know that
> > you
> > can measure just about anything given the right test equipment. I don't
> > really appreciate it enough, but one of the great advantages of my job
> > is
> > that I do have the unbelieveable luxury of getting my hands on this
> > stuff
> > whenever I need it. My problem is I don't have the time to play around
> > with
> > it.
> >
> > R,
> >
> > Al
> >
> >
> > > -----Original Message-----
> > > From: Paul Christensen [mailto:paulc@mediaone.net]
> > > Sent: Friday, 01 February 2002 5:10 AM
> > > To: Ten Tec
> > > Subject: Re: [TenTec] RE: More About Clix
> > >
> > >
> > > The operative word here is "reasonable." Al, I don't
> > > disagree with your
> > > statement in the least, but for most of us, securing a vector signal
> > > analyzer simply isn't an option for our measurements.
> > >
> > > -Paul, W9AC
> > >
> > > ----- Original Message -----
> > > From: "LORONA,AL (A-USA,ex3)" <al_lorona@agilent.com>
> > > To: "Ten Tec" <tentec@contesting.com>
> > > Sent: Friday, February 01, 2002 0:59 AM
> > > Subject: [TenTec] RE: More About Clix
> > >
> > >
> > > >
> > > > I posted a reply about measuring "microchirp" yesterday but
> > > it never made
> > > it
> > > > to the list. Here's my second try:
> > > >
> > > --------------------------------------------------------------
> > > ------------
> > > -
> > > >
> > > > >>You can't. In fact, I know of no electronic instrument capable
> > of
> > > > >>reasonably detecting it. Sometimes the ear is the best
> > > judge. The
> > > keyed
> > > > >>waveform oscilloscope display has no association with
> > > frequency shift.
> > > >
> > > > >>-Paul, W9AC
> > > >
> > > >
> > > > In fact, you can. You need an instrument that can capture a
> > > signal without
> > > > missing any data and then play it back while displaying
> > > frequency vs.
> > > time.
> > > > Such an instrument is called a vector signal analyzer.
> > > >
> > > > The VSA scrolls through a display of the spectrum of the
> > > signal. In this
> > > > way, the horizontal axis is frequency and the vertical
> > > axis is time. If
> > > the
> > > > plot is in color, the color can represent amplitude. This
> > > type of display
> > > > format is called a "spectrogram". I think some PSK-31
> > > programs (like
> > > > Digipan?) show the spectrum; just imagine successive
> > > spectra scrolled in
> > > the
> > > > display. It's hard to describe.
> > > >
> > > > Markers can be used to measure delta freq and delta time.
> > > This is how
> > > folks
> > > > measure the start-up transient behavior of PLLs and other
> > > oscillators,
> > > and
> > > > how law enforcement agencies positively identify a
> > > specific transmitter
> > > by
> > > > it's start-up "fingerprint".
> > > >
> > > > Al W6LX
> > > >
> > > > _______________________________________________
> > > > TenTec mailing list
> > > > TenTec@contesting.com
> > > > http://lists.contesting.com/mailman/listinfo/tentec
> > >
> > >
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> > >
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> >
>
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