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