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S/N numbers for Olivia

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  • Brian Lloyd
    I have been noticing that the S/N numbers displayed by fldigi when running the olivia mode seem to be wildly optimistic. They seem to be 20dB or so high. Does
    Message 1 of 7 , Nov 30, 2008
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      I have been noticing that the S/N numbers displayed by fldigi when
      running the olivia mode seem to be wildly optimistic. They seem to be
      20dB or so high. Does anyone know what algorithm is being used?

      --

      73 de Brian, WB6RQN
      Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
    • w1hkj
      ... See src/include/jalocha/pj_mfsk.h in the source tree for fldigi 3.03. // MFSK trasnmitter and receiver code, Pawel Jalocha, December 2004 This is the
      Message 2 of 7 , Nov 30, 2008
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        Brian Lloyd wrote:
        > I have been noticing that the S/N numbers displayed by fldigi when
        > running the olivia mode seem to be wildly optimistic. They seem to be
        > 20dB or so high. Does anyone know what algorithm is being used?
        >
        > --
        >
        > 73 de Brian, WB6RQN
        > Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
        >
        See src/include/jalocha/pj_mfsk.h in the source tree for fldigi 3.03.

        // MFSK trasnmitter and receiver code, Pawel Jalocha, December 2004

        This is the original code made public by Pawel and also used in the
        gMFSK implementation of Olivia.

        Please let me know if you see any error in the computation of SyncSNR.

        Thanks.

        Dave, W1HKJ
      • Brian Lloyd
        ... Thanks for the pointer Dave. To be honest, I don t know how it should work. I could read the code but I wouldn t know if the algorithm was correct. Perhaps
        Message 3 of 7 , Nov 30, 2008
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          On Nov 30, 2008, at 5:41 PM, w1hkj wrote:

          > Brian Lloyd wrote:
          >> I have been noticing that the S/N numbers displayed by fldigi when
          >> running the olivia mode seem to be wildly optimistic. They seem to be
          >> 20dB or so high. Does anyone know what algorithm is being used?
          >>
          >> --
          >>
          >> 73 de Brian, WB6RQN
          >> Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
          >>
          > See src/include/jalocha/pj_mfsk.h in the source tree for fldigi 3.03.
          >
          > // MFSK trasnmitter and receiver code, Pawel Jalocha, December 2004
          >
          > This is the original code made public by Pawel and also used in the
          > gMFSK implementation of Olivia.
          >
          > Please let me know if you see any error in the computation of SyncSNR.

          Thanks for the pointer Dave. To be honest, I don't know how it should
          work. I could read the code but I wouldn't know if the algorithm was
          correct. Perhaps it just uses a different reference. I am just trying
          out fldigi for the first time. I have been using DM780 which seems to
          reference to the apparent noise floor, not the absolute noise floor
          for the mode.

          One thing tho', it appears that fldigi has a 3-4dB advantage on DM780
          when decoding olivia, at least from my head-to-head comparison with
          both programs decoding the same data stream.

          --

          73 de Brian, WB6RQN
          Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
        • w1hkj
          ... The two should be very close to each other. Simon used most of fldigi s modem code for the background processing in DM780. Perhaps he made some changes
          Message 4 of 7 , Nov 30, 2008
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            Brian Lloyd wrote:
            On Nov 30, 2008, at 5:41 PM, w1hkj wrote:
            
              
            Brian Lloyd wrote:
                
            I have been noticing that the S/N numbers displayed by fldigi when
            running the olivia mode seem to be wildly optimistic. They seem to be
            20dB or so high. Does anyone know what algorithm is being used?
            
            --
            
            73 de Brian, WB6RQN
            Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
            
                  
            See src/include/jalocha/pj_mfsk.h in the source tree for fldigi 3.03.
            
            // MFSK trasnmitter and receiver code, Pawel Jalocha, December 2004
            
            This is the original code made public by Pawel and also used in the
            gMFSK implementation of Olivia.
            
            Please let me know if you see any error in the computation of SyncSNR.
                
            Thanks for the pointer Dave. To be honest, I don't know how it should  
            work. I could read the code but I wouldn't know if the algorithm was  
            correct. Perhaps it just uses a different reference. I am just trying  
            out fldigi for the first time. I have been using DM780 which seems to  
            reference to the apparent noise floor, not the absolute noise floor  
            for the mode.
            
            One thing tho', it appears that fldigi has a 3-4dB advantage on DM780  
            when decoding olivia, at least from my head-to-head comparison with  
            both programs decoding the same data stream.
              
            The two should be very close to each other.  Simon used most of fldigi's modem code for the background processing in DM780.  Perhaps he made some changes to the Olivia implementation.  I've cc'd him on this message.  Perhaps he can comment to you and/or the group.

            Dave, W1HKJ
          • Nate Bargmann
            Along these lines, since I worked my first Olivia QSO last night, I noted that the other station sent the S/N and freq offset in his return to me several
            Message 5 of 7 , Nov 30, 2008
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              Along these lines, since I worked my first Olivia QSO last night, I
              noted that the other station sent the S/N and freq offset in his return
              to me several times. He was using MixW as I recall. I looked through
              the macro tags but did not see any that would allow me to embed the
              same information back to him.

              BTW, it took me a bit to figure out that he was running 16/500 on his
              CQ transmissions which worked fine, at least much better than the PSK I
              was trying to copy. Many thanks for that "customize" option for Olivia.

              I guess this could be considered a feature request. :-)

              73, de Nate >>

              --

              "The optimist proclaims that we live in the best of all
              possible worlds. The pessimist fears this is true."

              Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
            • rich
              Nate, I expect this will be in the next version released, and it works well. My macro for RST is: ur rst with and It won t work
              Message 6 of 7 , Dec 1, 2008
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                Nate,

                I expect this will be in the next version released, and it works well.
                My macro for RST is: ur rst <rst> with <mode> <info1> and <info2>

                It won't work in current released version but it has been coded &
                tested by the developers.

                Rich
                WA4SXZ

                --- In linuxham@yahoogroups.com, Nate Bargmann <n0nb@...> wrote:
                >
                > Along these lines, since I worked my first Olivia QSO last night, I
                > noted that the other station sent the S/N and freq offset in his return
                > to me several times. He was using MixW as I recall. I looked through
                > the macro tags but did not see any that would allow me to embed the
                > same information back to him.
                >
              • Nate Bargmann
                ... Very well. I m looking forward to it. 73, de Nate -- The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this
                Message 7 of 7 , Dec 1, 2008
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                  * rich <richwa4sxz@...> [2008 Dec 01 07:08 -0600]:
                  >
                  > Nate,
                  >
                  > I expect this will be in the next version released, and it works well.
                  > My macro for RST is: ur rst <rst> with <mode> <info1> and <info2>
                  >
                  > It won't work in current released version but it has been coded &
                  > tested by the developers.

                  Very well. I'm looking forward to it.

                  73, de Nate >>

                  --

                  "The optimist proclaims that we live in the best of all
                  possible worlds. The pessimist fears this is true."

                  Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
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