VERTICAL SCROLLING METHOD FOR SCREEN DISPLAY WAVEFORM ON WAVEFORM RECORDOR

摘要

PURPOSE:To realize fast processing by adding or subtracting the number of dots, which is determined as one-line resolution in the lateral axis direction according to the relation with a display screen by a video RAM to or from the head address of the video RAM more than once and performing vertical scroll control. CONSTITUTION:The video RAM 15 adds or subtracts the number of dots which is determined as one-line resolution in the lateral axis direction according to the relation with the display screen to or from the head address 16 of the video RAM 15 determined corresponding to the current display state on the screen a desired number of times more than once to scroll up or down a display waveform on the screen as much as desired. Image data which are already stored in the video RAM 15 corresponding to the waveform data can be handled without rewriting the video RAM address even when the image needs to be scrolled, and the control procedure is facilitated correspondingly. Consequently, the fast processing is realized.