Then {HEAD ~ an analysis} on {TAIL ~ the states} of the M last 20ms blocks allows the final decision on voice presence 
Then { HEAD ~ an analysis } on { TAIL ~ the states } of the M last 20ms blocks allows the final decision on voice presence
OTH 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