In one example, the end of {TAIL ~ preamble} can occur only when the state machine is in {HEAD ~ two of four states} 
In one example , the end of { TAIL ~ preamble } can occur only when the state machine is in { HEAD ~ two of four states }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD