Electronic typographic apparatus

An alpha-numeric display system comprising a display device for displaying a line of characters wherein said display device is periodically scanned at a given rate to display said line,

• a memory,
• a constant frequency clocking means defining successive dot positions on the display,
• means for sequentially storing first coded signals in said memory corresponding to characters to be displayed in said line,
• a stepping circuit responsive to said first coded signals for asynchronously producing stepping signals selectively delayed an amount dependent upon the number of dot positions defined in the coded signals applied thereto, said number of dot positions corresponding to characters of various widths,
• means for applying said stepping signals to said memory for reading out signals stored therein, means for applying said coded signals read out of said memory of said stepping circuit,
• character generating means responsive to coded signals read out of said memory for activating said display device to display the corresponding characters,
• means providing coded back space signals, and
• means responsive to said coded back space signals for sequentially deleting the first coded signals from said memory, in such a manner that said first codes signals are deleted from said memory in an order reversed to the order at which they were stored.

An alphanumeric display system comprising a display device for displaying a line of characters wherein said display device is periodically scanned at a given rate,

• a memory having a plurality of storage locations,
• a source of first coded signals corresponding to proportional characters to be displayed, said characters having various widths,
• means for applying said first coded signals to said memory,
• a source of second coded signals corresponding to a backspace function,
• a source of stepping pulses connected to sequentially, asynchronously and nondestructively read out data stored in said different locations of said memory,
• means responsive to read out of said memory for (i) determining the time intervals between successive stepping pulses in accordance with the various character widths, and (ii) activating said display device to display said proportional characters corresponding to the first coded signals read out from said memory,
• first and second counters,
• means responsive to said stepping pulses for stepping said first counter,
• means for stepping said second counter in one direction in response to said first coded signals and in the other direction in resonse to said second codes signals,
• means responsive to a coincidence of counts of said first and second counters for enabling the storage in said memory of a first coded signal applied thereto, and
• means responsive to said second coded signals at the time of said coincidence for deleting a first coded signal stored in said memory.

An alphanumeric display system comprising a display device for displaying a plurality of lines of characters wherein the lines of the display device are sequentially scanned at a given rate,

• a plurality of memories of a number equal to the number of display lines, each memory having a plurality of storage locations,
• means for storing first coded signals in said memories whereby first coded signals in each memory correspond to characters of various widths in a separate line of text,
• means for sequentially reading out the storage locations of each memory, one memory after the other in sequence,
• a source of line position count pulses corresponding sequentially to the different lines of the display,
• a souce of asynchronous stepping pulses corresponding sequentially to positions in said lines,
• means responsive to said line position count pulses for sequentially gating series of stepping pulses to separate memories for nondestructively reading out said memories,
• means responsive to coded signals read out of said memories to (i) generate said stepping pulses at line intervals corresponding to the widths of characters to be displayed, and (ii) activate said display device to display the corresponding character being read, whereby each memory corresponds to a separate line of said display, and
• means responsive to said line position count pulses for selectively controlling the occurrence of said display line position count pulses to change the correspondence between said memories and the display lines of said display device.

An alphanumeric display system comprising a display device for displaying a plurality of lines of characters wherein the lines of the display device are sequentially scanned at a given rate,

• memory means having a plurality of storage locations, means for storing first coded signals in said memory means representing a plurality of separate lines of text for display on said display device, each line comprising characters of various widths,
• means for sequentially and asynchronously reading out the storage locations of said memory means,
• a source of line position count pulses corresponding sequentially to the different lines of said display,
• a source of stepping pulses corresponding sequentially to positions in said lines of display, the time intervals between successive pulse corresponding to the widths of characters to be displayed,
• means responsive to said line position count pulses for sequentially gating series of said stepping pulses to storage locations of said memory means for nondestructively reading out said memory means,
• means responsive to coded signals read out of said memory means to activate said display device to display the corresponding character, whereby groups of storage locations of said memory means correspond to separate lines of said display, and
• means for selectively controlling the occurrence of said line position count pulses to change the correspondence between groups of storage locations of said memory means and the display lines of said display device.