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Re: [softrock40] How to measure IMD?

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  • Chris Wilson
    ... 15/06/2013 09:54 Sorry, sticky lap top keyboard, that was supposed to be *2* tones, not 828 tones, of course :) And I see you have just replied to this
    Message 1 of 61 , Jun 15, 2013
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      >>

      >> ----- Original Message -----
      >> Subject: Re: [softrock40] How to measure IMD?

      >>>
      >>>
      >>> I made an Audacity dual tone file with combined frequencies of 1330
      >>> Hz and 550 Hz, and checked the resulting file looked clean from the
      >>> audio card, on a `scope. I then ran it into the Softrock Ensemble II
      >>> RXTX audio input.

      >> As has been said this produces DSB.
      >> IQout http://www.m0kgk.co.uk/sdr/download.php is designed to
      >> produce a two-tone IQ signal for test purposes.

      >> 73 Alan G4ZFQ.



      > 15/06/2013 09:45

      > I never expected this thread to become this big! I already have IQ
      > Out, but didn't think it suitable fur two tone IMD testing. How does
      > it produce 828 tones, the setup screen only allows oe tone frequency
      > to be selected? What frequency is the second tone?

      > I have put a screen shot of the setup panel at
      > http://www.gatesgarth.com/setup.jpg


      > Thanks, still ploughing through all this discussion!!



      15/06/2013 09:54

      Sorry, sticky lap top keyboard, that was supposed to be *2* tones, not
      828 tones, of course :)

      And I see you have just replied to this Alan, will go get the other
      app and try that, cheers.

      --
      Best Regards,
      Chris Wilson. 2E0ILY
    • warrenallgyer
      cause IMD, as measured using the ARRL protocol, is specified with reference to PEP, which is accepted to be 6 dB higher than the two tone level. I would be
      Message 61 of 61 , Jun 18, 2013
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        'cause IMD, as measured using the ARRL protocol, is specified with reference to PEP, which is accepted to be 6 dB higher than the two tone level.

        I would be interested to see the mil protocol and specification if you have it.

        Lucy
        (AKA Warren Allgyer - 9V1TD)


        --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
        >
        > The ARRL spec is the 6dB gift method not the mil method. If you add 6dB to the two tone level why don't you add 6dB to the IP3 also since it is the result of the two tones. Splain that Lucy.
        > I'm attending the school of hard knocks trying to modify a 1200 watt MRI board to HF. Fairly easy to make power but a different issue to get good IMD on all bands.
        > Frank WA1GFZ
        >
        >
        >
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