Abstract: A data processing system comprises a first selection device for selecting a plurality of characters of a first set, the characters of the first set each being defined by a bit map of first predetermined dimensions. A second selection device is capable of selecting a plurality of characters of a second set, the characters of the second set each being defined by a bit map of second predetermined dimensions greater than the first predetermined dimensions. A display device is capable of displaying the selected characters of the first and second sets, and a control device is responsive to the first and second selection devices for controlling the display device to display the selected characters of the first set in a first display area and the selected characters of the second set in a second display area, the first dislay area representing a page of text of characters of the first set, and the second display area representing a magnified portion of the page of text comprised of characters of the second set.

Abstract: A data communication system includes a communicating medium and a plurality of transceivers connected to the medium, each including a transmitter for transmitting phase-encoded data onto the medium and a receiver for receiving phase-encoded data communicated on the medium by another transceiver. A digital phase decoder is coupled to the receiver of each transceiver for decoding the data received and applying at its output a decode signal representative of the character of the received data. The received data comprises a plurality of bitcells each of a predetermined time period with a predetermined number of bitcells representing a data packet.

Abstract: Apparatus is disclosed for controlling the movement of a movable element to bring the movable element to rest at a desired stopping position. The apparatus comprises a multi-phase drive motor having a drive shaft coupled to the movable element for driving same, four electrically conductive coils mounted in position-displaced relationship about the shaft, and means coupled to the drive shaft and responsive to the selective energization of the coils by respective motor drive signals for causing the corresponding rotation of said drive shaft and movement of said movable element. A sensor is coupled to the drive shaft and is responsive to the rotation thereof for generating an electrical signal containing information indicative of the direction, speed and distance of movement of said movable element. Further, means are included for detecting from the distance information indicated by the electrical signal whether the movable element is within a predetermined distance of said desired stopping position.

Abstract: Apparatus is disclosed for controlling the movement of a movable element to bring the movable element to rest at a desired stopping position.

Abstract: Apparatus is disclosed which is responsive to the movement of a movable element for generating a plurality of electrically phase-displaced signals containing information indicative of the direction, speed and distance of movement of said movable element. The apparatus comprises a plurality of position-displaced electrically conductive coils and a permanent magnet mounted adjacent each of said coils for producing a path of normally substantially constant magnetic flux adjacent each of said coils. A flux varying device is coupled to the movable element and is responsive to the movement of the movable element for varying the level of the magnetic flux adjacent each of the coils in dependence upon the direction, speed and distance of movement of the movable element, whereby the resultant electromotive force induced in each of the coils defines the plurality of electrically phase-displaced signals.

Abstract: Apparatus is disclosed for controlling the movement of a movable element between an initial starting position and a final stopping position.

Abstract: Apparatus is disclosed for controlling the movement of a movable element between an initial starting position and a final stopping position. The apparatus comprises drive means coupled to the movable element and responsive to motor drive signals for moving the movable element along a predefined path between said starting and stopping positions; and first generating means for generating a first command velocity signal having a first state when the actual velocity of the movable element exceeds a predetermined value and a second state when the actual velocity of the movable element is less than the predetermined value.

Abstract: Apparatus is disclosed which is responsive to the movement of a movable element for generating a plurality of electrically phase-displaced signals containing information indicative of the direction, speed and distance of movement of the movable element. The apparatus comprises a plurality of position-displaced electrically conductive coils; a permanent magnet mounted adjacent each of the coils for producing a path of normally substantially constant magnetic flux adjacent each of the coils; and a flux varying device coupled to the movable element and responsive to the movement of the movable element for varying the level of the magnetic flux adjacent each of the coils in dependence upon the direction, speed and distance of movement of the movable element, whereby the resultant electromotive force induced in each of the coils defines the plurality of electrically phase-displaced signals.

Abstract: A print hammer assembly is disclosed comprising a support structure having a plunger at a first location thereon, and means for movably mounting the support structure with its plunger adjacent an electromagnetic actuator capable of being selectively energized such that, when the actuator is energized, the resultant magnetic field acting upon the plunger will cause the plunger and thus the support structure to travel along predefined paths and predetermined speeds. A hammer element is coupled to the support structure at a second location thereon, and means coupled to the hammer element causes the hammer element to impact an adjacent platen or interposed print element against an adjacent platen more than once during travel of the pole piece along its predefined path. The means for causing includes means for altering the location of maximum impact force of the hammer element following initial impact thereof against the platen or the interposed print element against the platen.

Abstract: A print hammer assembly is disclosed comprising a support structure having a plunger at a first location thereon, and means for movably mounting the support structure with its plunger adjacent an electromagnetic actuator capable of being selectively energized such that, when the actuator is energized, the resultant magnetic field acting upon the pole plunger will cause the plunger and thus the support structure to travel along predefined paths at predetermined speeds. A hammer element is coupled to the support structure at a second location thereon, and means coupled to the hammer element causes the hammer element to impact an adjacent platen or an interposed print element against an adjacent platen more than once during travel of the pole piece along its predefined path.

Abstract: A data processing system comprises a first storage device for storing character font data representative of a plurality of characters, each character being represented by the font data as a bit map of predetermined dimensions, the plurality of characters being stored in an ordered storage sequence. An image presentation device is capable of visually presenting an image comprised of preselected ones of the characters on a predetermined background area. A second storage device is capable of storing a bit map representation of the image, and a visual control device is capable of controlling the image presentation device to visually present the image in accordance with the character font data stored in the bit map representation of the image in the second storage device.

Abstract: A power amplifier is disclosed for controlling the current flow through a load, such as a d-c servo motor. The amplifier includes a plurality of switching elements connected in bridge fashion with the load and a predetermined power source for coupling the load across alternate output terminals of the power source in accordance with the levels of a plurality of control signals respectively coupled to the plurality of switching elements. Logic circuitry, when enabled, couples each of the control signals to their respective switching elements for controlling same. Sensing circuitry is coupled to the load for generating an actual current signal indicative of the actual level of current flow through the load. A current limiter is coupled to the sensing circuitry for comparing the actual current signal with high and low level limit signals and for generating a current disable signal when either the actual current signal exceeds the high limit signal or the low limit signal exceeds the actual current signal.

Abstract: A data communication system includes a communicating medium and a plurality of transceivers connected to the medium, each including a transmitter for transmitting phase-encoded data onto the medium and a receiver for receiving phase-encoded data communicated on the medium by another transceiver. A digital phase decoder is coupled to the receiver of each transceiver for decoding the data received and applying at its output a decode signal representative of the character of the received data. The decode signal is at a predetermined value whenever data communicated on the medium by another transceiver is received by the subject receiver during the time the subject transmitter is transmitting data onto the medium. Circuitry is included for interrupting the transmission of data whenever the decode signal is detected to be at said predetermined value.

Abstract: An adapter is provided as an interface between a raster output scanning printer and an electronic image processor which formats digital information for use by the printer in creating printed images. The adapter accepts digital pulses through a structured array of communication lines from the electronic image processor. Each line is dedicated to the provision of certain video or control information which may be utilized by any one of a number of different raster output scanning printers. The electronic image processor is indifferent to the identity of the type of printer to which information is provided as the adapter serves to manipulate the data provided by the electronic image processor in a manner suitable to control the particular printer employed. The adapter is sensitive to the scanning cycles of the printer and accommodates deviations in scan time to increase or decrease the rate of provision of video information in accordance with fluctuations in printer motor speed.

Abstract: A record material feed apparatus for use with a printing machine of the type including a platen and drive means for rotating the platen about its longitudinal axis. The apparatus comprises a frame capable of being attached to a printing machine adjacent the platen thereof, first and second drive shafts each rotatably mounted on the frame, and first and second drive assemblies respectively mounted on the first and second drive shafts, each drive assembly including means for engaging a marginally punched record material loaded thereon and means for feeding said record material in response to the rotation of the respective drive shaft. Further, a drive assembly is mounted on the frame and includes means for engaging the platen drive means and means responsive to such engagement and the operation of the drive means for rotating the first and second drive shafts in opposite directions.

Abstract: Apparatus is disclosed for controlling the current flow through first and second loads, such as motors, to thereby control the direction and speed of the motors. The apparatus comprises a first power amplifier connected to the first motor and including an oscillator for generating an oscillator signal having a predetermined frequency of oscillation and circuitry responsive to the oscillator signal for developing a first control current through the first motor. A second power amplifier is connected to the second motor and includes circuitry responsive to the same oscillator signal for developing a second control current through the second motor. The oscillator signal is coupled from the oscillator of the first power amplifier to the circuitry of the second power amplifier, whereby the second power amplifier is slaved to the first power amplifier.

Abstract: A power amplifier is disclosed for controlling the current flow through a load. The power amplifier includes a plurality of switching elements connected in bridge fashion with the load and a first predetermined power source for coupling the load across alternate output terminals of the power source in accordance with the levels of a plurality of control signals respectively applied to the plurality of switching elements. Circuitry is coupled to a second predetermined power source for generating the control signals. Logic circuitry, when enabled, is capable of coupling each of the control signals to the respective switching element. A power monitor circuit compares the voltage level of the second power source with a predetermined reference potential and generates a current disable signal when the voltage level is less than the reference potential.

Abstract: In a printer including a record material movable past a printing station, and a print assembly capable of printing a line of characters in dot matrix format upon relative movement of the print assembly and the record material in a first direction, a method and apparatus is disclosed for printing the line of characters. In accordance with such method and apparatus, the print assembly and record material are first moved relative to one another in the first direction at a first predetermined speed. Then, the print assembly is activated to print a first predetermined number of dots of the dot matrix pattern defining each character in the line. This is followed by moving the print assembly relative to the record material a predetermined amount in a second direction perpendicular to the first direction, and effecting relative movement of the print assembly and the record material in a third direction opposite the first direction.

Abstract: A pin feed apparatus is provided for a printing machine of the type including a main frame and a printing station. The pin feed apparatus is capable of feeding marginally punched record material past the printing station and includes a shaft rotatably mounted to the main frame, a platen mounted about the shaft for rotation therewith, and a pin wheel feeding device for feeding marginally punched record material disposed about the platen past the printing station. The pin wheel feeding device includes a housing coupled to the shaft adjacent an end of the platen for rotation therewith. The housing has a plurality of openings formed therein and the pin wheel feeding device further includes a cam member fixed in position relative to the housing and a plurality of pins disposed within the housing in respective alignment with the plurality of openings.

Abstract: A method of transferring data between a data supply and a disk having a track divided into sectors, each sector having an address recording area followed by a data recording area. The method includes detecting a defective area on a data recording area; writing an address of the defective area on the corresponding address recording area; recording data on the data recording area by detecting the defective area with the address and writing part of the data on the data recording area up to the defective area, and writing the remaining data on the data recording area succeeding the defective area; and retrieving the written data by reading the address of the defective area and then reading the recorded data. The apparatus includes a circuit to record a test pattern on the disk, a circuit to sense the recorded test pattern and provide an address of a defective area, a circuit to write the address on the address recording area, a circuit to write data on the disk, and a circuit to read the recorded area.