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