[GPS_Standard] Interesting paper

[Bob Stewart]

Dave says: 
"As I understand it (from the technology and from reading Shera's original QST article) the PLL approach comes along with one fairly stern requirement:  you have to manually tune the oscillator to within a gnat's whisker before it can phase-lock.  It has a narrow capture range.  My guess is that if you haven't already tuned the oscillator to within a fraction of one cycle per sample-averaging period, it won't lock"

Dave, I have experienced this myself in code that I haven't released, but hope to, in time.  This is the one we discussed, where I had a pretty tight lock, and when it fell out of the capture zone I issued another DAC update to attempt to push it back in.  However, with my version, it's not necessary to manually set things up.  It reaches the "zone" pretty quickly.  The problem is keeping it there.

Bob