Azelio wrote:
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 serious use.
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.
See, e.g.: 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 <https://en.wikipedia.org/wiki/Phase_detector> <https://jaunty-electronics.com/blog/2012/09/exclusive-or-xor-gate-based-phase-detector/> <http://memo.cgu.edu.tw/jtkuo/files/eelab%202014(iii)/1230_lab12_expxx_phaselockedloop.pdf> and many, many, many others. Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
