(under subclass 328) Subject matter wherein there is included a known frequency light source which may be part of the test emission source, an entrance slit, a dispersing means, a plurality of exit slits, one of which is associated with the known frequency dispersed by the dispersing means, a photosensitive detector responsive to the known light frequency received through its exit slit, and servo control means responsive to the detector to adjust the relative position of the dispersing means and the entrance or exit slits.
(1) Note. This subclass excludes recording spectrophotometers having a movable dispersing element to allow successively different light wavelengths to appear at the same exit slit, and having its movement mechanically synchronized to move the recorder and adjust the exit slit for the various wavelengths. See subclasses 321+ for this type of mechanically synchronized slit adjustment.
