The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 05, 1991
Filed:
Apr. 11, 1990
Andrew J Morrish, Eastleigh, GB;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A vertical scan circuit for a display is described which allows automatic picture height and centering. The deflection voltages at the start and end of active video time, are stored by capacitors fed via switches activated by signal pulses. These stored voltages are compared to margin reference voltages Vtmref and Vbmref which correspond to the desired top and bottom of the picture as displayed for a particular monitor. The maximum deflection voltage on flyback (Vmax) and the slope of the signal (dv/dt) are adjusted so that the top margin voltage (Vtm) and the bottom margin voltage (Vbm), bear desired relationships to these reference voltages (Vtmref and Vbmref respectively), thus ensuring that the top and bottom of the picture as displayed remains constant for different screen formats.