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