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Re: FFT export

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  • rrgsti
    If you re in a pinch, there s a Log Power Data option at the bottom of the AutoTuner section in this release:
    Message 1 of 6 , Oct 27, 2012
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      If you're in a pinch, there's a 'Log Power Data' option at the bottom of the AutoTuner section in this release:

      https://public-xrp.s3.amazonaws.com/Release-latest.zip

      This is from a really old code base, so many of the latest enhancements are not in there. But it might work in a pinch.

      The output format is tab delimited and looks something like this:

      10/27/2012 03:55:28.662 PM 104476000 2048000 4096 -80.34882 -82.94548

      First field is timestamp, second is center frequency, third is sample rate/bandwidth, fourth is FFT bins and the remaining (in this case, 4096) fields are the power level at each bin along the baseband.

      If you want higher resolution, just bump the FFT resolution up in the Display section. Your mileage may vary, however, as it spews a TON of data. If you want fine resolution, you might need to reduce sample rate. It spits out a new row at every FFT refresh, 50ms intervals by default.

      If you want to sample a wider range, you can do the 'roll center' option in the autotuner to cause the center to be retuned on regular intervals...this allows a bit of a 'survey'. I used that to get this image:

      https://public-xrp.s3.amazonaws.com/test.png

      Hope that helps.

      Bob

      --- In SDRSharp@..., Ian MM6DOS <ian@...> wrote:
      >
      >
      > Hi Rob
      >
      > I haven't used SpectrumLab but I wonder if an I/Q Wave file recording from the rtlsdr device can be used as the source and FFT'd ?
      >
      >
      > Ian"Rob, M0DTS" <rob@...> wrote:Hi All,
      >
      > Is there any way to export/grab the fft spectrum values easily?
      > I am wanting to do some external analysis of the spectrum plot once i have the data...
      >
      > I have used SpectrumLab to do this previously with soundcard but that does not support rtlsdr yet it seems.
      >
      > My knowledge of c# is none existent so modifying code to dump spectrum data to a file maybe a little much at present!
      >
      > Any other methods are welcome!
      >
      > Thanks
      >
      > Rob
      > M0DTS
      >
    • Rob, M0DTS
      Thanks for that, will take a look if I don t get anywhere myself.. I have downloaded VS Express for C# and compiled sdrsharp straight away with no problem...
      Message 2 of 6 , Oct 27, 2012
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        Thanks for that, will take a look if I don't get anywhere myself..

        I have downloaded VS Express for C# and compiled sdrsharp straight away with no problem... rare luck for me.

        The render function of SpectrumAnalyzer code (using _points[].Y) looks ok for me to drop a file write in so might just get it done myself ;-)

        Rob
        M0DTS

        On 27/10/2012 21:01, rrgsti wrote:
         

        If you're in a pinch, there's a 'Log Power Data' option at the bottom of the AutoTuner section in this release:

        https://public-xrp.s3.amazonaws.com/Release-latest.zip

        This is from a really old code base, so many of the latest enhancements are not in there. But it might work in a pinch.

        The output format is tab delimited and looks something like this:

        10/27/2012 03:55:28.662 PM 104476000 2048000 4096 -80.34882 -82.94548

        First field is timestamp, second is center frequency, third is sample rate/bandwidth, fourth is FFT bins and the remaining (in this case, 4096) fields are the power level at each bin along the baseband.

        If you want higher resolution, just bump the FFT resolution up in the Display section. Your mileage may vary, however, as it spews a TON of data. If you want fine resolution, you might need to reduce sample rate. It spits out a new row at every FFT refresh, 50ms intervals by default.

        If you want to sample a wider range, you can do the 'roll center' option in the autotuner to cause the center to be retuned on regular intervals...this allows a bit of a 'survey'. I used that to get this image:

        https://public-xrp.s3.amazonaws.com/test.png

        Hope that helps.

        Bob

        --- In SDRSharp@..., Ian MM6DOS <ian@...> wrote:
        >
        >
        > Hi Rob
        >
        > I haven't used SpectrumLab but I wonder if an I/Q Wave file recording from the rtlsdr device can be used as the source and FFT'd ?
        >
        >
        > Ian"Rob, M0DTS" <rob@...> wrote:Hi All,
        >
        > Is there any way to export/grab the fft spectrum values easily?
        > I am wanting to do some external analysis of the spectrum plot once i have the data...
        >
        > I have used SpectrumLab to do this previously with soundcard but that does not support rtlsdr yet it seems.
        >
        > My knowledge of c# is none existent so modifying code to dump spectrum data to a file maybe a little much at present!
        >
        > Any other methods are welcome!
        >
        > Thanks
        >
        > Rob
        > M0DTS
        >


      • Enildo Sánchez
        Hello Rob, Do you want to obtain spectrum plot from IQ data, with LabVIEW? I have used LabVIEW for firsts steps. Ecosierra.   From: Rob, M0DTS
        Message 3 of 6 , Oct 27, 2012
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          Hello Rob,
          Do you want to obtain spectrum plot from IQ data, with LabVIEW?
          I have used LabVIEW for firsts steps.
          Ecosierra.
           


          From: "Rob, M0DTS" <rob@...>
          To: SDRSharp@...
          Sent: Saturday, October 27, 2012 12:48:06 PM
          Subject: [SDRSharp] FFT export

           
          Hi All,

          Is there any way to export/grab the fft spectrum values easily?
          I am wanting to do some external analysis of the spectrum plot once i have the data...

          I have used SpectrumLab to do this previously with soundcard but that does not support rtlsdr yet it seems.

          My knowledge of c# is none existent so modifying code to dump spectrum data to a file maybe a little much at present!

          Any other methods are welcome!

          Thanks

          Rob
          M0DTS



        • rrgsti
          That s the best way to do it, get exactly what you need. Also note the GetSpectrumSnapshot() method in the plugin interface if you want to keep it relatively
          Message 4 of 6 , Oct 28, 2012
          • 0 Attachment
            That's the best way to do it, get exactly what you need.

            Also note the 'GetSpectrumSnapshot()' method in the plugin interface if you want to keep it relatively immune to trunk updates.

            You may also find that offset tuning (click 'configure' and check the box if you're using the RTL frontend) and IQ correction (check 'Correct IQ' box) will eliminate a good many artifacts in the data.

            --- In SDRSharp@..., "Rob, M0DTS" <rob@...> wrote:
            >
            > Thanks for that, will take a look if I don't get anywhere myself..
            >
            > I have downloaded VS Express for C# and compiled sdrsharp straight away
            > with no problem... rare luck for me.
            >
            > The render function of SpectrumAnalyzer code (using _points[].Y) looks
            > ok for me to drop a file write in so might just get it done myself ;-)
            >
            > Rob
            > M0DTS
            >
            > On 27/10/2012 21:01, rrgsti wrote:
            > >
            > > If you're in a pinch, there's a 'Log Power Data' option at the bottom
            > > of the AutoTuner section in this release:
            > >
            > > https://public-xrp.s3.amazonaws.com/Release-latest.zip
            > >
            > > This is from a really old code base, so many of the latest
            > > enhancements are not in there. But it might work in a pinch.
            > >
            > > The output format is tab delimited and looks something like this:
            > >
            > > 10/27/2012 03:55:28.662 PM 104476000 2048000 4096 -80.34882 -82.94548
            > >
            > > First field is timestamp, second is center frequency, third is sample
            > > rate/bandwidth, fourth is FFT bins and the remaining (in this case,
            > > 4096) fields are the power level at each bin along the baseband.
            > >
            > > If you want higher resolution, just bump the FFT resolution up in the
            > > Display section. Your mileage may vary, however, as it spews a TON of
            > > data. If you want fine resolution, you might need to reduce sample
            > > rate. It spits out a new row at every FFT refresh, 50ms intervals by
            > > default.
            > >
            > > If you want to sample a wider range, you can do the 'roll center'
            > > option in the autotuner to cause the center to be retuned on regular
            > > intervals...this allows a bit of a 'survey'. I used that to get this
            > > image:
            > >
            > > https://public-xrp.s3.amazonaws.com/test.png
            > >
            > > Hope that helps.
            > >
            > > Bob
            > >
            > > --- In SDRSharp@...
            > > <mailto:SDRSharp%40yahoogroups.co.uk>, Ian MM6DOS <ian@> wrote:
            > > >
            > > >
            > > > Hi Rob
            > > >
            > > > I haven't used SpectrumLab but I wonder if an I/Q Wave file
            > > recording from the rtlsdr device can be used as the source and FFT'd ?
            > > >
            > > >
            > > > Ian"Rob, M0DTS" <rob@> wrote:Hi All,
            > > >
            > > > Is there any way to export/grab the fft spectrum values easily?
            > > > I am wanting to do some external analysis of the spectrum plot once
            > > i have the data...
            > > >
            > > > I have used SpectrumLab to do this previously with soundcard but
            > > that does not support rtlsdr yet it seems.
            > > >
            > > > My knowledge of c# is none existent so modifying code to dump
            > > spectrum data to a file maybe a little much at present!
            > > >
            > > > Any other methods are welcome!
            > > >
            > > > Thanks
            > > >
            > > > Rob
            > > > M0DTS
            > > >
            > >
            > >
            >
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