Abstract: An automatic skew calibration technique for a multi-channel signal source uses a cross-coupled flip-flop calibration circuit and a microprocessor to align the timing of a pair of signals from the multi-channel signal source. The flip-flop calibration circuit indicates which of the pair of signals is leading, and the microprocessor uses the output of the flip-flop calibration circuit to determine in which signal source to adjust the signal delay. The signal source is incrementally delayed by the microprocessor while the microprocessor also observes the output of the flip-flop calibration circuit. When the flip-flop calibration circuit indicates a time interval over which the relative time position of the input signals changes, then the microprocessor determines a calibrated value for the signal delay, completing skew calibration of the multi-channel signal source.

Abstract: A thermometer-to-binary encoder includes a set of J input stage encoders E(1) through E(J) and an output encoder D, where J= 2.sup.K is an integer greater than 1. A set of digital input signals each representing a separate bit of a thermometer code T is grouped into J signal subsets representing further thermometer codes T(1) through T(J) providing inputs to a set of input stage encoders E(1) through E(J) respectively. Encoder E(J) produces an N-K+1 bit output binary code B(J) representing thermometer code T(J). Encoders E(1) through E(J-1) produce M-bit output binary codes G(1) through G(J-1), respectively, comprising the lower M bits of a binary code representing thermometer codes T(1) through T(J-1), respectively, where M is an integer greater than 1. Output encoder D processes codes G(1) through G(J-1) and B(J) to produce a set of digital output signals representing a binary code Y representing input thermometer code T.

Abstract: A drop-on-demand ink jet print head (9) has an ink pressure chamber (22) coupled to a source of ink (11) and an ink drop ejecting orifice (103) with an ink drop ejection orifice outlet (14). An acoustic driver (36), in response to a drive signal (100), produces a pressure wave in the ink and causes the ink to pass outwardly through the ink drop ejecting orifice (103) and the ink jet ejection orifice outlet (14) of the ink jet print head (9). In accordance with the present invention, controlling the operation of the ink jet print head (9) with a particular drive signal reduces print quality degradation resulting from rectified diffusion, which is the growth of .air bubbles dissolved in the ink from the repeated application of pressure pulses to the ink residing within the ink pressure chamber (22) of the ink jet print head (9), such pressure pulses causing the application of pressures below ambient pressure.

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 controller (124) analyzes a set of OTDR return data stored in a memory (134) and determines if a particular event is an echo by comparing its measured location and/or amplitude (loss) with calculated locations (208) and amplitudes for various-order echoes. Possible echoes are optionally assigned an echo probability level (220, 224, 228) based on the degree to which their measured locations and/or amplitudes match the calculated echo locations and amplitudes. Possible echoes are appropriately marked (210) so that an OTDR display (136) indicates to a user which events are possible echoes. Optionally, events may be marked as having a low, medium, or high probability of being echoes.

Abstract: A phase change ink composition is indirectly applied to a substrate by raising the temperature of the phase change ink composition to form a liquid phase change ink composition, applying droplets of the phase change ink composition in a liquid phase to a liquid intermediate transfer surface on a solid support in a pattern using a device such as an ink jet printhead, solidifying the phase change ink composition on the liquid intermediate transfer surface, transferring the phase change ink composition from the liquid intermediate transfer surface to the substrate, and fixing the phase change ink composition to the substrate. The phase change ink composition is malleable when the ink is transferred from the intermediate transfer surface to the substrate and is ductile after the ink has been transferred to the substrate and cooled to ambient temperature to preclude the ink from crumbling and cracking.

Abstract: A method for characterizing an event in acquired digital data is described where the event has a known shape and a pattern having amplitude and location coefficients is applied to the data for determining a best fit between the data and the pattern as a function of a peak RMS value. The derived RMS value is compared to a threshold value for verifying the existence of the event. The event is characterized as to amplitude and location using the amplitude and location coefficients of the pattern. Such a method is useful in characterizing non-reflective events in acquired optical time domain reflectometry data.

Abstract: A method allows analog device model descriptions to be described in a suitable language and then automatically converted into the language of the simulator in a form that facilitates gradient-based calculations. The method can include the steps of: entering a high-level description of the component model by naming the model, declaring parameters, specifying argument-independent equations, describing a topology of the model, declaring arguments, and specifying argument-dependent equations.

Abstract: An auto selecting scrolling device is an improved user interface for viewing and making selection of a parameter from a menu. When a device, used to scroll through a menu, is activated the menu appears. A timer with user preset time limit is started. As long as the scrolling device is being used to scroll through the parameters in the menu, the timer is reset. While the scrolling is taking place the parameters are not only highlighted but also magnified. If the menu is no longer being scrolled through, then the timer expires upon attaining the user set limit. When the timer expires, the last highlighted parameter is selected and the menu is closed.

Abstract: A rotating print medium retaining clamp is disclosed which securely clamps the print medium or printed image final receiving surface to prevent horizontal or X-axis misregistration while drawing the print medium in a generally circular path through the nip between the platen and the print head. Only the retaining clamp assembly rotates while the support guide remains stationary. The support guide has space for a printing platen to be positioned along the print medium guide path.

Abstract: A hue control circuit for adjusting the color phase of a composite PAL television signal without demodulating the chrominance component of the composite PAL television signal uses a polyphase interpolator to change the phase of the modulated chrominance component. A set of coefficients corresponding to a desired hue adjustment is applied to the polyphase interpolator. A hue coefficient address circuit addresses a coefficient memory containing a plurality of sets of coefficients, the sets being in complementary pairs. During each horizontal blanking line interval for a given desired hue adjustment the hue coefficient address circuit swaps the sets of coefficients between the complementary pair defining the desired hue adjustment in synchronization with the alternating sign of one of the color difference components of the modulated chrominance component on a line by line basis.

Abstract: An improved sample and hold signal generator produces very short delay intervals between successive sample-to-hold transitions that are both collectively and individually adjustable. A plurality of capacitors are charged to a precharge level upon the occurrence of a precharge signal and discharged to the threshold level of a plurality of amplifiers through a plurality of constant current sources upon the occurrence of a discharge signal. When the voltage on a particular capacitor is discharged to the threshold level, the associated amplifier produces a sample-to-hold signal transition and the voltage level of a signal being sampled is stored on a capacitor. In successive cells of the sample and hold generating means the threshold level is reached at incrementally varying delay times that are separated by approximately equal time intervals.

Abstract: An optical time domain reflectometry method and apparatus that employs Hadamard transforms to increase the signal-to-noise ratio. A sequence of N pulses of light corresponding to a Hadamard derived code are launched down a fiber optic cable for each of N such codes. Selected combinations of pulses of reflected light are transformed by a Hadamard derived matrix to a set of equations that are solved simultaneously to determine the power reflected from each of N points. Where a Hadamard code is used the average mean square error is reduced by a factor of 1/N. Where a simplex code is employed the average mean square error is reduced by a factor of 4N/(1+N).sup.2. In addition, N measurements of the power reflected at each point are computed and averaged.

Abstract: A multi-channel trigger dejitter technique uses actual digitized samples from a repetitive waveform signal to correct for jitter in a hardware trigger signal. Interpolated samples are calculated between a set of the digitized samples about the hardware trigger signal, and a hardware trigger level is determined from the closest sample in time to the hardware trigger signal. The hardware trigger level is averaged with that determined from prior acquisitions to produce an average trigger level. The closest sample in time to the average trigger level becomes an averaged trigger signal, and the times for all the digitized samples for that acquisition, as well as all simultaneous acquisitions from other input channels, are adjusted according the difference in time between the hardware and averaged trigger signals. Over several acquisition iterations of the repetitive waveform the amount of jitter between acquisitions is decreased.

Abstract: An apparatus and method for dynamic memory allocation conserves memory resources while providing efficient and effective interaction between concurrent synchronous and asynchronous acquisition of data for logic analysis. The apparatus includes circuitry for acquiring synchronous data, circuitry for acquiring asynchronous data, circuitry for generating timestamp values, circuitry for determining when the synchronous data is valid, circuitry for determining when the asynchronous data is valid, and circuitry for packing valid synchronous data and valid asynchronous data into a memory according to the sequence in which it was acquired with sufficient timestamp values included to permit reconstruction of the relative timing between all of the acquired data, with each data and timestamp value being identified with status bits to indicate whether it was synchronous data, asynchronous data, or a timestamp value.

Abstract: Automatic extraction of pulse parametrics from multi-valued functions, such as a digital serial communications signal, is achieved by building up an eye pattern data array from multiple acquisitions of the multi-valued functions. One axis of the data array represents amplitude and another represents time, and the contents of each element of the array represents the number of times a data point occurs within the amplitude-time interval represented by the element during the multiple acquisitions. After the data array has been built, histograms representing summations of selected elements of the data array are obtained. From the histogram information the pulse parametrics are determined, such as amplitude levels for the various states of the signal as well as the characteristics of transition paths between states.

Abstract: A finite impulse response (FIR) digital filter (100, 170, 175, 180) incorporates both symmetric and transposed structures in a configuration that suites ASIC implementation. The filter coefficients can be arranged in ascending order to implement coefficient block floating point, or in descending order. To further facilitate coefficient block floating point, filter coefficients are chosen so that each cell has an exponent value equal to or greater than that of a preceding cell. A right shift is provided between adjacent cells to equate the exponent value of a sum output of a preceding cell with that of the succeeding cell. Variable decimation is provided by downloading appropriate filter coefficient and adjusting a decimation forward clock. Multiple channels can also be accommodated.

Abstract: An interface system allows a user to select and control colors used in graphic images generated by a computer system. The interface system employs graphical representations of the hue, chroma, and lightness combinations capable of being rendered by a computer graphics system. In a preferred embodiment, the graphical representation includes a one-dimensional graph (40) depicting the range of hues and a two-dimensional graph (42) depicting the range of chroma and value combinations available for a selected hue. The graphical representations are preferably rendered in accordance with a Hue-Value-Chroma ("HVC") color space (90) having a high degree of perceptual uniformity.

Abstract: A digital data generation system including a programmable dominance RS flip-flop has a random access memory that stores a user selected sequence of test data. A pattern formatting logic circuit receives the test data and produces, for each data period, a coarsely timed candidate pulse for identifying the leading edge of an output data pulse and a coarsely timed candidate pulse for identifying the trailing edge of the output data pulse. A precision delay circuit finely tunes the timing of the candidate pulses. The finely tuned pulses are applied to an RS flip-flop circuit which can be programmed for set or reset dominance, thereby preventing an indeterminate state when a logic "1" is applied to both the set and the reset input. In the system, the flip-flop is programmed so that the most recent of the lead pulse or the trail pulse prevails.