{HEAD ~ A hearing aid apparatus} employs {TAIL ~ a single side band modulator} which serves to convert an audio band of frequencies into an upper and lower side band signal 
employs
{ HEAD ~ A hearing aid apparatus } employs { TAIL ~ a single side band modulator } which serves to convert an audio band of frequencies into an upper and lower side band signal
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH