Abstract: An optical time domain reflectometer (OTDR) is treated as a linear shift-invariant system modeled as a ideal resistive-capacitive network. A step pulse is applied to a fiber under test and the return optical energy from the fiber under test is converted to signal samples representative of the return optical energy. The signal samples are processed in a controller for producing step impulse stimulus signal samples corrected for the bandwidth limited system response of the optical time domain reflectometer by modeling the OTDR as an exponential linear shift-invariant system that includes the optical transmitter, optical receiver and the fiber under test. The controller takes the time derivative of the step impulse stimulus signal samples for generating signal samples representative of the impulse response for the fiber under test.

Abstract: An improved method for controlling the optical density of an image printed by an electrostatic printer is provided. The method compensates for optical density drift over the useful life of a toner receptacle by adjusting the voltage vector between the photoconductive belt and the toner particles. The method calculates an overall toner usage amount and adjusts the voltage vector when the amount reaches one or more predetermined values. In this manner, the present method controls the optical density of a printed image over the useful life of the toner receptacle.

Abstract: Reactive ink compositions of the present invention utilize at least two reactive components, a base ink component and a curing component, that are applied to a receiving substrate separately. The base ink component includes an ink carrier, a compatible colorant, and a cross-linkable constituent, and the curing component is a cross-linking agent. Upon exposure of the base ink component to the curing component, at least a portion of the ink is cross-linked to provide a printed image that is durable and abrasion-resistant.

Abstract: A digital halftone pattern geometry adapted not to the characteristics of variable dot size printing presses but to the operating characteristics of the printer itself achieves a high degree of image quality. The techniques for creating the halftone pattern geometry include linear spot growth to provide uniform darkening and the use of a super-cell structure to maximize the number of tint or gray scale levels. A preferred super-cell structure is of hexagonal dispersed-dot form to reduce low frequency artifacts by spreading them over a greater number of frequencies. Hexagonal centered super-cells also distribute row and column artifacts along three axes of symmetry instead of two. The super-cell structure gives sharp edges and a greater amount of edge area available to manipulate when the super-cells are tessellated to form an image. This halftone cell arrangement is especially suited to thermal transfer printers, which print linear rows and form good rectangular shapes.

Abstract: This invention is a resistive layer (112, 122) for electrodes (30, 62) comprising at least one partially conductive compound and describes processes for coating the electrodes by way of cataphoretic deposition and/or screen printing of particles of at least one partially conductive compound. A second class of particles, known as a "frit," is also deposited or screen printed. In the subsequent one hour firing, these particles melt and thereby bond the partially conductive compound particles to the electrodes. This invention is also plasma addressing structures (110, 120) in which particles of at least one partially conductive compound are deposited on the electrodes of the display by cataphoretic deposition and/or screen printing. The resulting electrode structures limit and uniformly distribute discharge currents (102) in the operation of ionizable gaseous medium (90) devices, such as plasma addressed liquid crystal displays.

Abstract: A method of fabricating a channel structure for a PALC display panel comprises providing a channel member having channels formed in its upper surface and two electrodes in each channel, masking one electrode in each channel while leaving the other electrode unmasked, depositing material on the unmasked electrode in each channel, and removing the mask from masked electrode in each channel.

Abstract: A method for depositing an image on a receiving surface utilizing two scans of a print head is provided. Each scan deposits a portion of the image, and the two scans are separated by a non-deposition skip move. The two image portions are joined at a seam to create a composite image. By utilizing identical print head motions along the x-axis direction for all images, this method allows for accurate and repeatable image-half alignment regardless of image width, length or position on the receiving surface.

Abstract: An algorithm for distributing video buffer rate control over a parallel compression architecture uses parallel processors to first compute complexity measures for each macroblock of a current picture. Based upon the complexity measures a master controller determines target rates for each slice of the current picture. A set of slices are then encoded in parallel by the parallel processors acting as microrate controllers, each slice being encoded based solely upon its own target rate. After the set of slices are encoded, the target rates are adjusted for the remaining slices based upon the actual rates from the encoded slices, and the next set of slices is encoded in parallel based upon the updated target rates. After each macroblock within a slice is encoded, a VBV fullness check is made to detect if VBV overflow or underflow is likely to occur. In such an event emergency action is taken to prevent such overflow or underflow.

Abstract: Generation of digital cursors for serial digital television waveform monitors includes inputting hexadecimal values for the cursors by an operator via a front panel. The hexadecimal values are received by a microprocessor which loads them into appropriate registers of a co-processor. The outputs of the cursor registers in the co-processor are input to respective inputs of a multiplexer together with a digital signal representing a serial digital television signal. A select signal for the multiplexer is generated by a selection circuit that is enabled by a digital cursor ON command when the waveform monitor is in a cursor mode. The selection circuit at predetermined locations of the digital signal generates the select signal so that the appropriate cursor values are inserted into the digital signal at those locations.

Abstract: A computer printer having a frame contained within a housing, a media transport and printing mechanism attached to the frame within the housing is provided with at least one debris shield positioned above the printing mechanism to protect it from falling debris. The at least one debris shield may be positioned below an air flow path generated by printer ventilation, and the printer may employ a transfer surface on which an image is generated prior to transfer to a media sheet, and above which the debris shield is positioned.

Abstract: A CMOS buffer amplifier can accept input signals and produce output signals that are within one half of the enhancement threshold voltage of the power supply voltages. These characteristics make this buffer amplifier ideal for use with low voltage CMOS circuitry with sub-micron geometries. The buffer amplifier contains two differential amplifiers, the output of both being combined and coupled to an output node. Each differential amplifier has matched input transducing devices on each of its inputs. One of these couples the input of the buffer amplifier to one of the inputs of the differential amplifier, while the other one couples the output of the buffer amplifier as feedback to the other side of the same differential amplifier. The pair of input transducing devices providing input to one differential amplifier are matched and suitable for operation in a higher voltage range than are the matched pair providing input to the other differential amplifier.

Abstract: An improved serial-digital data receiver that receives a scrambled NRZI voltage signal representing a transmitted serial-digital data signal converts the scrambled NRZI voltage signal in the analog domain to a bi-polar or pseudo-ternary voltage signal. The bi-polar voltage signal is then input to a slicer and clock recovery circuit to provide a recovered clock signal and a scrambled NRZ data signal in the digital domain. The scrambled NRZ data signal is then descrambled to recover the transmitted serial-digital data signal. Single bit error identification and limited correction may be included by using a sequential state machine decoder to generate an error flag and by using a "soft-decision" circuit to identify the probable bit error location.

Abstract: A switcher using shared processors has an input matrix with a plurality of inputs to which a corresponding plurality of sources may be coupled. One or more of the sources may provide compressed data. The input matrix routes selected ones of the sources to a plurality of outputs which is less in number than the number of inputs, the routing being determined by a tally output. A pool of processors, such as compression decoders, color correctors or the like, are coupled to the outputs of the input matrix as needed for processing those sources that require such processing to provide processed data. The outputs of the processors provide processed data to a conventional switcher that combines the selected processed data to provide a program output. The conventional switcher also provides the tally output.

Abstract: A first comparison circuit compares an internally generated clock signal with a reference signal and produces a first error signal in response to timing differences between rising edges of the clock signal and the reference signal. A second comparison circuit compares the internally generated clock signal with the reference signal and produces a second error signal in response to timing differences between falling edges of the clock signal and the reference signal. The first and second error signals are applied to control inputs of a phase shifter chain to control delay in each stage to reduce the timing error with respect to each edge.

Abstract: Attentional maps that reflect the subjective view of an observer to the effects of degradation in a video image are used in the objective measurement of video quality degradation. The observer assists in generating an attentional map for each image of a test image sequence, which provides different thresholds or weighting factors for different areas of each image. A video image sequence from a system under test is compared with the test image sequence, and the error results are displayed as a function of the corresponding attentional maps.

Abstract: A method for measuring interference in a cable transmission system includes the step of establishing a spectrum frequency measurement window having start and stop frequencies and an amplitude threshold. Data is acquired over the window representative of the spectral energy of the cable transmission system within the window and the data is compared against the threshold value. If the data falls below the threshold value, indicating the absence of a carrier signal within the window, a display is generated characterizing the interference over the window. Additional measurement windows may be established having different start and stop frequencies and thresholds for measuring different portions of the cable transmission system frequency spectrum.