DISPLAY APPARATUS

摘要

The display apparatus comprises an output time-base corrector (OTC) that receives a digital linear saw-tooth (VR) as a vertical position indicator. A correction stage receives a multiplication factor (PMF) and/or DC-shift factor (PDC) for multiplying and/or DC-shifting the digital linear saw-tooth (VR) to obtain a corrected saw-tooth (CVR) that is supplied to a frame deflection circuit (DAC1, VDC). The DC-shift factor (PDC) is adjusted such that a midpoint (MP) of the corrected saw-tooth (CVR) coincides with a center (CE) of the display screen (SCR) in the direction of the frame scan. The multiplication factor (PMF) is adjusted to obtain a desired amplitude of the frame scan. Now, the corrected saw-tooth (CVR) provides a frame scan which is centered in the frame direction and which has the desired amplitude. Consequently, after this adjustment, the digital linear saw-tooth (VR) has become a position reference for the frame scan and thus is a one to one indication of the position in the frame scan direction on the screen (SCR).