Typically, some subband data is replaced with zeros so that an error causes {HEAD ~ some} of {TAIL ~ the frequency components} to be lost 
Typically , some subband data is replaced with zeros so that an error causes { HEAD ~ some } of { TAIL ~ the frequency components } to be lost
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH