Interferometers 341 and 342 generate {HEAD ~ electronic signals} 347 and 348, respectively, which are transmitted to {TAIL ~ electronic controller} 350 where they are processed to determine the position of stage 320 in the x direction and changes in the angle of bar mirror 346 in the plane of FIG 3 
Interferometers 341 and 342 generate { HEAD ~ electronic signals } 347 and 348 , respectively , which are transmitted to { TAIL ~ electronic controller } 350 where they are processed to determine the position of stage 320 in the x direction and changes in the angle of bar mirror 346 in the plane of FIG 3
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH