Re: [LAD] Jitter analysis

Please find the attached XL sheet which has the data of read & write timings.

Both read and write are of same length

alpha & beta coefficients are
  float c1 = 0.017771532; /* alpha */
  float c2 = 0.000157914; /* beta */
  
 Audio Control loop local FIFO has two buffers, 1920 samples/buffer

aud_ctrl_err.xlsx
<http://linux-audio.4202.n7.nabble.com/file/t2646/aud_ctrl_err.xlsx>
  

Fons Adriaensen-3 wrote
> On Sat, Sep 16, 2017 at 10:17:04PM -0700, benravin wrote:
>
>> I'm facing a timing jitter which happens periodically due to some
>> interrupt,
>> which is causing the task to be delayed. Since this happens periodically,
>> it
>> is indeed a slow varying timing jitter, for example every 400ms, the
>> timing
>> deviation is in the order of few ms ( 4-6ms). This is not getting
>> filtered
>> out by DLL, and results in a slow varying oscillations which never dies.
>>
>> Any way to identify and limit these timing jitters and not to take any
>> action on drift correction by DLL ?
>
> It's impossible to say anything about this if you don't provide
> numbers. How big is the resulting resampling ratio variation ?
>
> If a few ms jitter leads to anything perceptible then your DLL
> and/or resampling control loop are not dimensioned correctly,
> or there is another basic problem with your design.
>
> Ciao,
>
> --
> FA
>
> A world of exhaustive, reliable metadata would be an utopia.
> It's also a pipe-dream, founded on self-delusion, nerd hubris
> and hysterically inflated market opportunities. (Cory Doctorow)
>
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-----
-ben

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