Re: PLL lock detector
Some chips have a lock detector pin on them already, others you have to design one yourself.
For the standard discrete phase frequency detector chip, you get pulses of random frequency out of the phase detector when it is not locked. You AC couple that to a shottky diode, and store the charge generated across a capacitor. Once the voltage across the capacitor rises beyond a threshold point, you sense that with a comparator that reports the out-of-lock condition.
Rich