Display apparatus having variable text row formating

摘要

A circuit is described for selectively increasing the number of text rows on the display screen of a CRT. The number of scan lines in each text row is reduced by one in response to a display format selection signal. The scan lines so saved are utilized to form two additional text rows. A variable modulus scan line counter is used in combination with a decoder to provide the scan line counter modulus desired. Additionally, a text row counter is used in combination with a second decoder to selectively change the modulus of the text row counter to correspond with the selected modulus of the scan line counter. A compressed display is provided by simultaneously changing the modulus of both the scan line and text row counters.