[time-nuts] PLL Math Question

Bob Stewart bob at evoria.net
Wed Mar 12 13:24:19 EDT 2014

Now that I've got the TIC going, I'm working on the PLL math for my GPSDO.  My question is about moving averages.  I've put in a moving average for the TIC.  From that, I've calculated the slope, and have put a moving average on the slope to settle it down.  I think this boils down to a moving average of a moving average.  If both are 16 seconds long, is this essentially a 32 second moving average of the TIC, or is it some other function?  I read briefly about averages of averages last night, but I'm not sure I understood the conclusion.  This is all "clean code" so I may be over-complicating things, but I'm OK with that.

NOTE: The reason I'm using 16 seconds is that I'm becoming memory limited.  I'm switching to an 18F2320, but that only gets me more program memory.  I'm constrained to this chip on an existing board.

Bob - AE6RV

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