Real world effects such as {HEAD ~ filtering}, multipath time spread, and time base error destroy orthogonality and introduce a degree of cross coupling between {TAIL ~ supposedly orthogonal channels} 
Real world effects such as { HEAD ~ filtering } , multipath time spread , and time base error destroy orthogonality and introduce a degree of cross coupling between { TAIL ~ supposedly orthogonal channels }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL