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627RE: RE: RX Window For Commerical Radio Inerface

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  • do1fjn
    Oct 23, 2013
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      Hi all,


      I would say: "optimum" RX level is 1.0Vpp (with a well modulated GMSK signal). In the case of using better / improved GMSK demodulation algorithm (viterbi / soft decision) it's better to have a not-clipped NF signal.


      In the moment it's not necessary to (external) adjust the RX NF level like CMX- based solutions...



      P.S.:

      We still search developers who have fun and skills to improve the firmware or add new functions. I can implement almost all algorithms, but my knowledge to calculate digital filters and fitting PLL are not the best...


      73 de

      Jan, DO1FJN




      ---In DVRPTR_V1@yahoogroups.com, <dvrptr_v1@yahoogroups.com> wrote:

      Jan,

      understood

      thanks..

      73 -

      Tony

      NN1D




      ---In dvrptr_v1@yahoogroups.com, <ke2n@...> wrote:

      the instructions say:
       
      "RX does not need level adjustment. The DVRPTR board detects a wide range of voltage levels. The signal from the 9k6 jack of your FM transceiver to the DVRPTR board should be in the range of 0,5Vpp to 2,5Vpp for best performance."
       
      It would  be nice if it said: "optimum performance results at 1.5 volts pk-pk   ;-)
       
      One very weak user of my system starts each transmission with a burst of R2. No doubt his signal is slightly off frequency.  I am going to lower the level from 2.5 to 1.5 volts now that I know the full story.
       
      Tnx & 73
       
      Ken
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