[time-nuts] RC TIC linearity correction?
bruce.griffiths at xtra.co.nz
Wed Mar 26 13:22:14 EDT 2014
A random source will need a lot more samples in each bucket to reduce
the noise to an acceptable level.
To determine the relative bucket width with a 10% error requires at
least 100 samples per bucket.
For 1% error at least 10,000 samples per bucket.
All thats really required is a sufficiently noisy oscillator that isn't
phase locked to your clock.
>>> I hadn't given any thought to correcting the linearity of the TIC I
>>> built, but my PLL plots tell me I should do it now.
> One method would be to calibrate with a series of buckets that you
> fill by sampling a random source, the more samples in a bucket the
> more range in phase for that bucket. For example 1 1 1 2 2 2 3 2 2 1 0
> samples sum equal 17 so each unit equal 17/(total range of TIC) and
> the bucket with 3 samples would be 3 * 17/(total range of TIC).
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