{HEAD ~ A second pair} of signals is derived from the first pair of signals in which the second pair are displaced in {TAIL ~ phase} relative to the first pair and are also in phase quadrature 
{ HEAD ~ A second pair } of signals is derived from the first pair of signals in which the second pair are displaced in { TAIL ~ phase } relative to the first pair and are also in phase quadrature
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH