Phase Detector for 12nSec square signals chip

Inquiry Description: Hi All I'm looking inside the AD product in order to choise the right chip to realize a quite Low Frequency phase detector. My goal is keep in phase two pulsed signals (Pulse duration= 12nS, Pulse amplitude range= +2 : +8 V, Pulse frequency range= 10KHz : 1MHz, Pulse shape = Square wave, Pulses delay range = 0 : 12 nSec.) The Pulses delay is digitally controlled => Each step delay is fixed = 100pSec.
 
Thanks in advance