{HEAD ~ The receiver} compares {TAIL ~ the difference} between the phase sector of the present symbol and the phase sector of a preceding symbol 
compares
{ HEAD ~ The receiver } compares { TAIL ~ the difference } between the phase sector of the present symbol and the phase sector of a preceding symbol
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