The second time difference may be {HEAD ~ a time difference} between {TAIL ~ falling edges} of the first component of the differential signal and the second component of the phase shifted signal 
The second time difference may be { HEAD ~ a time difference } between { TAIL ~ falling edges } of the first component of the differential signal and the second component of the phase shifted signal
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH