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Re: [softrock40] Re: Realtek 889 or Creative X-Fi / Delta 44 is there a big improvement ?

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  • Alan
    ... Subject: [softrock40] Re: Realtek 889 or Creative X-Fi / Delta 44 is there a big improvement ? ... Kelvin, The point I was trying to make with those tests
    Message 1 of 5 , Oct 24, 2012
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      ----- Original Message -----
      Subject: [softrock40] Re: Realtek 889 or Creative X-Fi / Delta 44 is there a big improvement ?


      >
      > I just took a look at your xonar test page, I did notice the pic of the HDSDR screen shot, for comparison I decided to do a screen
      > shot of HDSDR on the 889 i posted it at http://i.imgur.com/kpjs6.jpg while it does not show as much noise at the ends as the xonar
      > it seems pretty good for the "free price".

      Kelvin,

      The point I was trying to make with those tests is that these expensive cards sometimes do not deliver what their specifications
      suggest when used with SDR.
      That shot was taken with the input gain at a minimum so advantage can be made of the lower noise in the centre. But at 192KHz
      signals at the edges are masked by the noise. And in fact the soundcard noise in the centre is already swamped by noise from the
      Softrock.
      I can make a shot more like yours by increasing the soundcard input gain so the noise at the edges is hidden by the increased
      signal. Then ~25dB of dynamic range is lost.

      I see similar situation with the on-board 192KHz systems.
      But all soundcard SDR is a compromise so we each make our own decision. Knowing these compromises might help to us understand what
      is happening if a problem occurs.

      73 Alan G4ZFQ
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