Hi all, I'm building a WWV-locked ovenized oscillator as a local frequency standard for my cheap counter. I have all of the pieces of this gizmo figured out and built and working except for the frequency-phase detector. What kind of detector can be used as part of a PLL to lock the ovenized osc? The osc, btw, always comes within 1 Hz of WWV after about 1 hr warmup, but while I can detect the amount of phase error there is with a phase comparator, I dont know if its above or below WWV.