[Elecraft] KX3 SDR

[tomb18]

HiI have little experience in demodulation of the signals but I did do SSB and AM at one time. Basically once you have the samples in the fre1uency domain you will want to apply a bandpass filters and shift it down to baseband,  do an inverse fft and then a Hilbert transform to demodulate the SSB signal.Again you best bet is the free online book I mention.73 Tom 


Sent from my Samsung Galaxy smartphone.
-------- Original message --------From: Enzo Adrian-Reyes <enzo.adrianreyes at gmail.com> Date: 2016-07-27  8:04 PM  (GMT-05:00) To: tomb18 <tomb18 at videotron.ca> Cc: Elecraft List <elecraft at mailman.qth.net> Subject: Re: [Elecraft] KX3 SDR 
Hi Tom
I never thought it was simple :)
I am just trying to understand what is going on, so given by what you've said I would push the IQ data coming from the KX3 into an FFT, that FFT would then produce the circular buffer  that would  let me analyse what signals are in that band?
But this would be in the frequency domain then, however I am not interested in a band plot,  I have a signal at Freq X, with the KX3 tuned at Y, (X=Y), would I have to still pump that IQ data into the FFT to filter all the other signals out, then inverse teh FFT to get the IQ data that I would want?
Regards

On Thu, Jul 28, 2016 at 9:41 AM, tomb18 <tomb18 at videotron.ca> wrote:
Hi It's not that simple Basically you take the I and q signals, sample them with the sound card, convert them to a complex number, pop them  in a fast Fourier transform, do a rectangular to polar conversion and then calculate the magnitude in dBm.  Then plot them. There's a few more nuances but that's the overall idea. Check out the free book on the Internet called the scientists guide to digital signal processing.73 Tom va2fsq.com


Sent from my Samsung Galaxy smartphone.
-------- Original message --------From: Enzo Adrian-Reyes <enzo.adrianreyes at gmail.com> Date: 2016-07-27  7:16 PM  (GMT-05:00) To: Elecraft List <elecraft at mailman.qth.net> Subject: [Elecraft] KX3 SDR 
Hi All

Yes this topic might be a little bit more complicated than the title
suggest.

So I have the KX3 plugged into the audio input of my computer, and its
sending quadrature data (IQ) to the sound card, the sound card samples at
96Khz.

So my question is how I process this? Yes I know use a piece of software,
but I am trying to write this, I know the IQ data is coming through down
and if I use the right process on the IQ data I get base band data out. I
kind of know that however I dont understand the SDR data coming out, so for
example and I getting sample of IQ data at freq point Y, or is it  a
circular buffer arrangement.

I guess what I am saying is, is the IQ data coming from teh KX3 data from
teh Centre Freq (+/-) the bandwith scope, or just the centre freq + some
additional side bands?

How are bandwith and sampling rate related? I mean if I am sampling at at
96Khz, with a band with of 48Khz does that mean I am only getting 2 samples
per second at perticular freq??? Or am I getting the entire band of 48Khz
at 96Khz.

Regards
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