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