A correction signal is applied to the modulator to maintain substantially uniform exposure across {HEAD ~ the output medium} notwithstanding {TAIL ~ variations} in the velocity of the beam 
A correction signal is applied to the modulator to maintain substantially uniform exposure across { HEAD ~ the output medium } notwithstanding { TAIL ~ variations } in the velocity of the beam
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH