There are diffrent length pickups for the 20ppr, I have it going to a schmitt trigger after being amped, if you alter the gain of the amp the o/p will pick up on 1pps, 3pps, or the full 20pps, I'm using the latter to speed lock.
I'm using type 2 phase detect, mainly cause the duty cycle of the 20pps is way off 50%, the leading edges however line up, I dont use the phase pulse o/p, pin1.
I tried a pullup and pulldown 10k, killed the o/p altogther, the connection on the bvoard goes direct to the pickup, if its a passive pickup then thats to be expected, I tried holding a 1mH choke up next to the magnet ring, got the same o/p.
Interesting idea about the pixel clock, I'd need a multiplier rather than a divider though as theres only 3 or 4 encoder pulses over the displayed area.
Interesting about your idea of speed locking with 1pps and phase locking with 20pps, were you thinking speed lock with type 2 and phase lock with type 1 in the same chip?, how would I switch with the lock detect and what would I use for a freq ref for the 20pps signal.