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RMS Jitter From Phase Noise

strigois

I am trying to convert Phase Noise to RMS Jitter(radians), but I'm having trouble following the units through the process.

To get RMS Jitter, in radians, from Phase Noise you must integrate the Phase Noise.  What are the units of integrated Phase Noise and how do they cancel.  The equation I am currently using for this is A = Phase Noise (L(f)) + 10*log10(frequency2- frequency1) and to generate the RMS Jitter value in radians I am using sqrt(2*10^(A/10)).

Additionally, what are the units for 10*log10(frequency2- frequency1) and if L(f) is the ratio of Pcarrier and Poffset in dBm, and that has units of dBc/Hz, what would be the units if it were converted to a linear value.

Thank you for any insight you might have on these questions.

Parents

  • Hi Shawn,

    I follow your thinking about using a logarithmic scale when trying to do a trapezoidal approximation.  I was already working on converting the phase noise measurement to a linear value and crunching the numbers that way when I read your reply.  :) 

     

    Right now I'm doing research and not design work.  I don't have spurs within the first 3 decades of my measurements and very few with significance beyond that.  What I'm trying to determine is what the overall impact of additional noise, at varying frequencies, is on my oscillator and if it impacts its performance.  At this point the specific type of noise and jitter aren't super important to differentiate.  I just need to be certain the the values for jitter that I'm calculating are valid, and that I understand the process of they're calculation.  I think I'm at the point where I understand the calculations and am starting to see some relation between the phase noise I'm measuring and the jitter I'm calculating.

    Thank you for your help,

    Grant

Reply

  • Hi Shawn,

    I follow your thinking about using a logarithmic scale when trying to do a trapezoidal approximation.  I was already working on converting the phase noise measurement to a linear value and crunching the numbers that way when I read your reply.  :) 

     

    Right now I'm doing research and not design work.  I don't have spurs within the first 3 decades of my measurements and very few with significance beyond that.  What I'm trying to determine is what the overall impact of additional noise, at varying frequencies, is on my oscillator and if it impacts its performance.  At this point the specific type of noise and jitter aren't super important to differentiate.  I just need to be certain the the values for jitter that I'm calculating are valid, and that I understand the process of they're calculation.  I think I'm at the point where I understand the calculations and am starting to see some relation between the phase noise I'm measuring and the jitter I'm calculating.

    Thank you for your help,

    Grant

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