Abstract: A method and apparatus for performing data error detection and correction is disclosed for multi-level logic and in particular, three-level trinary logic of levels 0, 1, 2. A source of trinary data supplies individual pieces of data (trits of 0, or 1, or 2) in multiple trit groups (trytes) to two separate check trit generators which generate unique check trits for each tryte input. The check trits from the two check trit generators are compared to form syndrome trits which are used to control an error detection function. For single errors per tryte a data correction function is activated to increment or decrement the incorrect data through a multiplexer. Multiple errors or no error conditions are indicated, but do not gate the data correction function.

Abstract: A method and apparatus for performing data error detection and correction is disclosed for multi-level logic and in particular, three-level trinary logic of levels 0, 1, 2. A source of trinary data supplies individual pieces of data (trits of 0, or 1, or 2) in multiple trit groups (trytes) to two separate check trit generators which generate unique check trits for each tryte input. The check trits from the two check trit generators are compared to form syndrome trits which are used to control an error detection function. For single errors per tryte a data correction function is activated to increment or decrement the incorrect data through a multiplexer. Multiple errors or no error conditions are indicated, but do not gate the data correction function.

Abstract: A table driven print formatting system that accepts a text data stream including individual text commands and produces a printable data stream including individual print commands. The formatting system uses the text data in combination with printer status data to select subsection entries from a printer description table. The subsection entries include specific print command subsections each having print commands that can be placed immediately into the printable data stream upon selection. The table also includes general print command subsections which each have printer description data and a general print command shell. When a general print command subsection entry is selected, the printer description data is used in combination with the text data to calculate a parameter for inserting into the general shell thereby producing a print command for placing in the printable data stream. The printer description table also uses a unique entry indexing scheme that minimizes storage requirements for the table.

Abstract: In a microprogram-controlled processor, having an additional operating mode in which particular functions can be executed under direct hardware control, a mode latch signals whether microprogram instructions or directly controlled macro instructions are to be executed. The macroprogram instructions are conventionally executed. For the execution of directly controlled macro instructions, a control storage supplies a hardware control word associated with the macro instruction to be directly executed. The hardware control word contains a mode control bit for signalling that the direct hardware control mode is to be executed. The remainder of the hardware control word contains a plurality of direct control bits, each of which directly controls a hardware function. In an alternative embodiment multiple hardware control words are employed.

Abstract: A communications interface for transferring data from a first binary logic circuit to a second binary logic circuit by using a trinary logic transmission channel. The first set of binary logic signals is converted into a first set of binary control signals which, in turn, control trinary drivers connected to the transmission channel. The trinary drivers drive the transmission channel to one of three discrete voltage levels as opposed to one of two levels in binary systems. Trinary receivers are located on the second binary logic circuit and are connected to the trinary transmission channel. The receivers produce a second set of binary control signals which are translated into a second set of binary logic signals for use by the second binary logic circuit.

Abstract: Operation of an AC plasma display panel requires the three control operations of write, erase, and sustain. Sustain, write and erase signals are stored in a plurality of sections in a storage device and the sections are selectively accessed according to the specific operation to be provided to the plasma panel display. The control signals stored within a given sequence are selected so that no dimming occurs during write and erase operations. A brightness control is provided to modulate the average repetition rate of signals applied to the plasma display panel. In this manner, a plurality of flicker-free brightness levels may be chosen.

Abstract: A method and system is disclosed for displaying and editing information without flicker. Vector branch commands as well as the vectors comprising the information to be displayed are both divided into two groups. The first groups are those branch commands and vectors required to display the information requested in a recognizable form. The second groups are those branch commands and vectors required to completely display the information requested. Editing operations are performed on the recognizable form of the information to eliminate flicker. A REFRESH END COMMAND or a REFRESH END INCREMENT X COMMAND can also be used to delineate the two groups of branch commands. The REFRESH END INCREMENT X COMMAND also allows the user to add details to the display over and above those normally provided for editing operations. Faster raster-scan display refresh operations are also made possible by writing/reading only the points necessary to recognizably display images.

Abstract: A driving system for a plasma panel display which uses VFETs for output switches controls the transition time of an output waveform to a constant time. Transformerless circuitry for communicating low voltage digital logic signals across a floating boundary to VFET control circuitry is provided. Low voltage control circuitry is isolated from high voltage sources by semiconductor circuitry which eliminates the need for transformer isolation techniques. In an alternative embodiment, the transition of an output waveform is controlled at a constant slew rate.

Abstract: A document indexing method and apparatus facilitates access to sequentially stored documents in a word processing system. The invention uses random access memory in the word processor to build a page index when the sequential data stream is first processed. The page index is then available so that subsequent access to previously processed pages is faster than conventional sequential access. The page index has associated with it an offset index having pointers to the actual entries in the page index. If the page index proves too small to store a index entry for every single page of a document, the offset index is reorganized to point to every other entry in the page index. Reorganization effectively doubles the span of pages covered by the page index and may be repeated a plurality of times to allow a sequentially stored document of arbitrary length to be indexed by a fixed length page index.

Abstract: A transformer assembly suitable for use in very high frequency (VHF) switching power supplies that maintains a low leakage inductance between critical transformer windings while complying with the physical and electrical requirements imposed by standards for primary to secondary isolation. The transformer includes a telescopic bobbin assembly with an inner and an outer section that telescope together to form an interior clearance space or chamber between the two sections. The interior chamber has a narrow conduit exiting to the exterior of the bobbin assembly. Described are two embodiments for a transformer used in a forward-averaging type converter and a third embodiment for a transformer used in a frequency modulated converter.

Abstract: An optical data is transmitted from station to station through an optical T-coupler attached to each station. The optical T-coupler splits the data signals into two paths with identical data being transmitted to the attached station and also the succeeding station. An optical to electronic conversion takes place as the data enters the station. Electronic digital switching within each station selects a "normal" mode of receiving data from the preceding station when data is valid or a "bypass" mode of receiving data from the station which precedes the preceding station. Switching from normal to bypass mode is performed by electronic switching and requires no optical switches.

Abstract: A data transmission system which includes stations connected in a closed loop configuration with interface capabilities at each station to connect to an external data processor. Through this configuration simultaneous transmission of data among processors connected to stations on the loop can be carried out by transmission of data around the loop between particular stations. Data is transmitted from a first processor to its individual station connected to the loop. This first station formats the data received from the first processor into frames of multi-bit configuration which are transmitted around the loop to a second station which is connected to a second processor. Data received by the second station is stored and transmitted to the second processor. During the time that this transmission from the first processor to the second processor is being carried out a transmission between other processors connected to stations on the loop can also be carried out.