Each delay stage may be configured to phase shift {TAIL ~ a differential signal} based on {HEAD ~ a control signal} 
Each delay stage may be configured to phase shift { TAIL ~ a differential signal } based on { HEAD ~ a control signal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD