[time-nuts] PLL Math Question

[Hal Murray]

albertson.chris at gmail.com said:
> We have to define "best".  I'd define it as "the error integrated over time
> is minimum".  I think PiD gets you that and it is also easy to program and
> uses very little memory.  Just three values (1) the error, (2) the total of
> all errors you've seen (in a perfect world this is zero because the positive
> and negative errors cancel) and (3) the rate of change in the error (is it
> getting bigger of smaller and how quickly?)  Multiply each of those numbers
> by a constant and that is the correction to the output value. 

I think you are off by a factor of 2.  There are 6 parameters, 2 for each of 
3 channels.  Each channel has gain and time-constant.  There are separate 
channels/parameters/whatever-you-call-them for P, I, and D.



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