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Re: [softrock40] Re: USB Audio device

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  • k5nwa
    Given a good 192KHz vs 48KHz there is an advantage to 192KHz, when you decimate the signal down to narrow the bandwidth in the software if the proper
    Message 1 of 8 , Aug 31, 2010
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      Given a good 192KHz vs 48KHz there is an advantage to 192KHz, when you decimate the signal down to narrow the bandwidth in the software if the proper algorithms are used you gain increased dynamic range and S/N ratios the more you decimate. But of course the benefits must be compared to the increased cost not just in dollars but also in term of CPU time required.

      That is why a Mercury card while it only has a 16 bit A/D with 14 bit accuracy because it samples at 60MHz or more that with the decimation required it ends up having better quality than a really good 24 bit card.


      On Tue, 31 Aug 2010 21:33:34 -0500, Tom Hoflich <km5h@...> wrote:



      Dan, I think you are exactly right.  I think the 96 and 192Khz thinking goes back to when we did not have
      the frequency agility of the Si570.  If you are crystal bound, the wider sampling does make sense.

      73, Tom
       

      From: Dan Schaaf <dan-schaaf@...>
      To: softrock40@yahoogroups.com
      Sent: Tue, August 31, 2010 8:49:12 PM
      Subject: Re: [softrock40] Re: USB Audio device

       

      Actually all I am planning to do is look up or down band maybe 20 to 30 KHz when working DX in the pileup. 48 KHz may be just fine for me.
       
      Not sure why I would need 96 or 192 KHz.
      But then, I am a newbie to SDR. I am only interested in receive anyway with Rocky or similar panadapter capability.
       
      Dan Schaaf
       
      My Chocolate Lab is smarter than your honor roll child
       
      ==================================
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      ----- Original Message -----
      From: Grant
      Sent: Tuesday, August 31, 2010 9:27 PM
      Subject: [softrock40] Re: USB Audio device

       

      Dan,

      I also use the XFi USB card with my Laptop. It sure works OK, although I have only used it at 48MHz sampling rate. My softrock is an RXTX v6.3 and I have good results on CW TX as well as digital mode receive. Haven't yet tried transmitting on the other modes, but I see no reason why the results will be any different.

      regards
      Grant VK4JAZ

      --- In softrock40@yahoogroups.com, "oceanbiz01" <dan-schaaf@...> wrote:
      >
      > I was involved in the topic a few days ago regarding a second sound card. I have the Realtek AC97 onboard Audio in my PC.
      > Well, I ordered the Creative XFI Surround 5.1 USB Sound card and it arrived today. I just simply plugged it into my USB port and Device Manager shows it under Sound, Video and Game Controllers/USB Audio Device. I did not even install the drivers. My Realtek AC97 is also shown. So, this USB Sound card did NOT override the AC97 as a PCI Soundcard did.
      > I then ran Rocky and looked in settings and I now have a choice of AC97 or USB Sound Card.
      > Next step will be to see if it actually works. I do not have the Softrock Lite II board built yet. But I can test the USB card with some other stuff.
      > So, my $50 gamble proved to be good.
      >
      > Dan K3ZXL
      >






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      Cecil

      k5nwa

      www.k5nwa.com www.dspradio.org www.yellowdogparts.com

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