Process for the control of a matrix screen having two independent parts and apparatus for its performance

A process for displaying data, during a frame, on a matrix screen having a first part and a second part, each said part having an even plurality of rows of number N, each said plurality of rows of each said part being organized into two pluralities of rows, a first plurality having a first parity and a second plurality having a second parity different from said first parity, each said part also having a plurality of independently addressable columns M, each said column of said first part crossing over all of the rows of said first part, each said column of said second part crossing over all of the rows of said second part, individual pixels of said screen being defined by points at which said columns cross over said rows, said frame to be displayed being divided into a first half-frame and second half-frame, said process comprising the steps of:

• a. successively selecting, during said first half-frame, successive rows of said first parity of said first part, while simultaneously successively selecting successive rows of said second parity of said second part that are paired with said successive rows of said first parity of said first part;
• b. successively selecting, during said second half-frame successive rows of said second parity of said first part, while simultaneously successively selecting successive rows of said first parity of said second part that are paired with said successive rows of said second parity of said first part;
• and
• c. displaying on rows selected during steps a and b, data supplied from a memory means and a video source with a regular timing and in an order related to successive rows of the screen, selection of said rows taking place at twice said regular timing, wherein during step a, data displayed on the rows of said first parity of said first part are supplied from the source and data displayed on the rows of said second parity of said second part are supplied from said memory means, and wherein during step b, data displayed on the rows of said second parity of said first part are supplied from said memory means and data displayed on the rows of said first parity of said second part are supplied from the source, the data supplied from said memory means during said first half-frame having been supplied from said source and stored in said memory means during a preceding half-frame, and the data supplied from said memory means during said second half-frame having been supplied from said source and stored in said memory means during said first half-frame, said memory means having a capacity for storing about one-fourth of the data displayed on said matrix screen during said frame.