[time-nuts] FLL errors
csteinmetz at yandex.com
Fri Aug 28 13:14:37 EDT 2015
>OK: the XOR gate with an RC is a defective PLL and a defective FLL. It
>is a simple way to have an idea of what an xLL should be but of no
No, not at all. I was suggesting that the XOR PLL you were
commenting on had problems.
First, an XOR with or without an RC is not an FLL at all, of any
sort. Second, the XOR gate is a time-honored phase detector for
PLLs, and if its limitations are understood and accounted for, it
makes a perfectly serviceable PD for a PLL. There are other phase
detectors that are more popular these days, for a variety of reasons,
but the XOR works just fine in a proper design.
Best, Phase-Locked Loops (2007), pp. 16-18
Gardner, Phaselock Techniques (3rd ed) (2005), pp. 245-46
Wolaver, Phase-Locked Loop Circuit Design (1991) pp. 55-59
and many, many, many others.
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