Individual signals representing the variable power component are combined with {HEAD ~ the error signal} to provide {TAIL ~ the individual control signals} for each power source 
to provide
Individual signals representing the variable power component are combined with { HEAD ~ the error signal } to provide { TAIL ~ the individual control signals } for each power source
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH