Analog correction system

Apparatus for compensating for nonlinear response characteristics of a display system for displaying graphical images on an energy responsive surface with a radiant energy beam and having beam deflection means for positioning said beam on said surface in response to deflection signals and wherein said deflection means has a nonlinear response characteristic which is substantially symmetrical with respect to a known deflection signal value whereby a deflection signal having a value greater than said known deflection signal value by a first amount requires a correction which is of the same magnitude but opposite polarity as the correction required by a deflection signal having a value which is less than said known deflection signal value by said first amount, said apparatus comprising:

• means for detecting the difference between the value of said deflection signal and said known deflection signal value and for providing a first output signal having a value dependent upon the magnitude of said difference and a second output signal having a value dependent upon the polarity of said difference;
• correction means responsive to said first output signal for providing a correction signal having a value in dependence thereupon;
• and
• combining means responsive to said deflection signal, said correction signal, and said second output signal for applying a correction to said deflection signal, said correction having a magnitude dependent upon said correction signal and a polarity dependent upon said second output signal so as to provide a compensated deflection signal for application to said deflection means.

Apparatus for compensating for nonlinear response characteristics of a display system for displaying graphical images on an energy responsive surface with a radiant energy beam and having deflection means responsive to X and Y deflection signals for controlling deflection of said beam, said apparatus comprising:

• means for providing X and Y deflection signals;
• on-axis correction means responsive to said X and Y deflection signals for providing an X on-axis correction signal having values functionally related to only said X deflection signal and a Y on-axis correction signal having values functionally related to only said Y deflection signal;
• off-axis correction means responsive to said X and Y deflection signals for providing X and Y off-axis correction signals each having values functionally related to both said X and Y deflection signals;
• and,
• means for additively combining said X deflection signal, said X on-axis correction signal and said X off-axis correction signal to produce a compensated said X deflection signal, and for combining said Y deflection signal, said Y on-axis correction signal and said Y off-axis correction signal to produce a compensated said Y deflection signal.

Apparatus for compensating for nonlinear response characteristics of a display system for displaying graphical images on an energy responsive surface with a radiant energy beam and having deflection means responsive to at least one deflection signal, said apparatus comprising:

• means for providing digital signals having values linearly representative of desired beam deflection;
• conversion means responsive to said digital signals for providing uncompensated analog deflection signals having values proportional to the values of said digital signals;
• compensation means responsive to said analog deflection signals for generating an analog compensation signal non-monotonically related thereto;
• and,
• means for additively combining said analog compensation signal and said analog deflection signal so as to provide a compensated said analog deflection signal for application to said deflection means.