[time-nuts] Fw: How to detect PLL lock

[Poul-Henning Kamp]

If you have a microcontroller, isn't it simpler to just look for
convergence in the development of the error term ?

You're probably not in any big hurry for exact convergence anyway,
so overdampen the PLL and simply check that the redidual decreases
towards zero.

Once you have locked the PLL, the fastest way to detect loss of
lock, in particular if you use too high time-constant, is the
too low frequency of zero crossings in the residual.

Poul-Henning


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