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DAX frequency accuracy

Andrew VK5CV
Andrew VK5CV Member ✭✭
edited June 2020 in SmartSDR for Windows
With digital modes on conventional sound cards clock timing and sampling frequency have an effect on frequency "calibration" What is the source of the clock in DAX? Does it derive from the radios reference or the PCs reference or both? Does that or any latency involved effect frequency accuracy in digital modes? I must admit I can't detect any error. Andrew


  • Andrew VK5CV
    Andrew VK5CV Member ✭✭
    edited February 2017
    It appears that there may be an error of 20ppm in the DAX handled signal in my case on one PC.
  • Andrew VK5CV
    Andrew VK5CV Member ✭✭
    edited February 2017

    VAC claims a clock correction accuracy of 1E-8%

    How good is DAX?


  • Patrick
    Patrick WH6HI KauaiMember ✭✭✭
    edited June 2020
    Since there are two parts to the DAX connection the part in the Radio and the part that interfaces with the Audio processing in the computer.  I would think that signal accuracy primarily originates at the radio end as a function of the radios reference clock which sets the frequency accuracy of the  Analog to Digital conversion.  So the resulting Audio will follow the radios accuracy.  At the computer end I  would think that it is the system clock which also sets the time.  DM-780 has a Audio Card frequency display and on my computer I see it stay within    8000.3 HZ +- .3 HZ or better  sometimes I see it at 8000.00 Hz.   It would be nice to have a Theory of operation section  in the manual that could answer many of these questions.  

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