Abstract: A portable electronic typewriter having a memory incorporating a low-cost spelling-check dictionary and including a multi-character display. The typewriter is operable in a "List" mode according to which the operator can call up display of a portion of the dictionary, sequentially in alphabetical order and one word at a time. The display consists of each stored word sharing an initial set, or "string", of n characters (termed a "template") defined by the operator via the keyboard of the typewriter. In a preferred version, when the typist becomes aware of uncertainty as to spelling, the List Mode may be initiated either before or after partial entry of the desired word. In particular, if the characters entered include an erroneous one, (the typist being alerted of this by an audible alarm, for example), initiation of the List Mode thereafter causes the string to be truncated just before the erroneous character.

Abstract: A method and apparatus for adding a low-cost spelling check dictionary feature to document preparation systems such as portable electronic typewriters, the spelling check being performed on a character-by-character basis and an error signal emitted upon the earliest determination that an input character does not conform to that of any word listed in the dictionary. Semiconductor ROM is used for storage of the dictionary listing and for program control of the spelling check. Text compression methods are utilized to permit storage of large vocabularies (about 35,000 words) while minimizing the ROM capacity required (about 3 IC's of 256K bits each).

Abstract: A low-cost spelling-check dictionary apparatus for incorportation in a portable electronic typewriter. Semiconductor ROM is used for storage of the dictionary's word listing and for program control of the spelling check. Text compression methods are utilized to permit storage of large vocabularies (about 35,000 words) while minimizing the ROM capacity required (about 3 IC's of 256K bits each). In particular, the words are alphabetically arranged in a set of three interconnected tables together with extensions of the third table in highly compressed fashion. The tables verify the spelling order of the first three character inputs, while the extensions verify the fourth and subsequent inputs, if any. The tables have a first "look-up structure" format, whereas the extensions are arranged in a different "tree structure" type of format utilizing a "Huffman code" for the characters.

Abstract: An electronic typewriter with an electronic spelling dictionary feature included therein automatically adds a code signal to a code memory register corresponding to a print position of a printed error. The printed error is detected by the dictionary feature in response to printing operations. The electronic typewriter also automatically repositions a print hammer of a printing mechanism to the printed error position from a position beyond the printed error. This is accomplished by an operator actuating a key or a multiple key sequence for finding the printed error by the electronics searching for and finding the added code signal.