The phase of {TAIL ~ a memory clock signal} is adjusted by advancing and delaying {HEAD ~ the phase} 
The phase of { TAIL ~ a memory clock signal } is adjusted by advancing and delaying { HEAD ~ the phase }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD