Showing papers on "Offset (computer science) published in 1988"

Characteristics of offset-structure polycrystalline-silicon thin-film transistors

Abstract: In order to reduce anomalous leakage current from n-channel polycrystalline-silicon thin-film transistors (poly-Si TFTs), an offset structure that has an n/sup -/ region between channel and n/sup +/ source-drain electrodes has been proposed. Drain-current measurements of the poly-Si TFT prove that the offset structure is effective in reducing the anomalous leakage current, and that the optimization of the offset length and the doping concentration in the offset region enlarge the ON/OFF current ratio. Implantation of 5*10/sup 13/ cm/sup -2/ phosphorus ions in the offset region makes the ON/OFF current ratio more than one order of magnitude larger than that of conventional structure TFTs. >

A second-order high-resolution incremental A/D converter with offset and charge injection compensation

Abstract: Measurement and instrumentation applications require absolute accuracy, e.g. offset and gain errors cannot be tolerated. These applications are characterized by DC performance such as differential and integral nonlinearities, offset and gain errors, and they often require high resolution. The second-order incremental A/D converter, which makes use of sigma-delta modulation associated with a simple digital filter, is capable of achieving such requirements. Experimental results of circuits fabricated in a SACMOS 3- mu m technology indicate that 15-bit absolute accuracy is easily achievable, even with a low reference voltage. >

Effect of frequency offset in DPSK phase-diversity optical receivers

Abstract: The effect of the frequency offset in DPSK phase-diversity receivers is discussed both theoretically and experimentally. In practical cases, the offset frequency should be chosen approximately 2% of the bit rate, giving 1.0 dB power penalty. >

Offset approximation of uniform B-splines

Abstract: A simple and efficient method is developed for generating offset curves interactively using a set of control knots for a uniform cubic B-spline.

Absolute position sensor having multi-layer windings of different pitches providing respective indications of phase proportional to displacement

Abstract: For enabling a resolver to have absolute position sensing over a wide displacement range while still obtaining the resolution, accuracy and precision obtainable by operation in an incremental mode, the resolver is provided with a number of terminals for providing offset pitch phase indications as a function of position. A microcomputer is programmed to execute a decoding procedure for reading the offset pitch phase indications and from them computing the absolute position. This method is applicable to linear as well as rotary position sensing. By using multiplexing, digital signal processing and large-scale circuit integration for interfacing the resolver to the microcomputer, the method can achieve absolute position sensing with high reliability and low cost. The offset pitch phase indications are readily provided by inductive coupling between a multiplicity of windings, including a set of offset pitch windings connected to the terminals. A phase indicating signal is picked up using either a relatively moving pick-up device or a stationary coil linked by a ferromagnetic core. A radio-frequency powered modulator is provided for wireless transmission of the phase indicating signal from the moving pick-up device. The offset pitch windings are formed by photolithography on a plurality of laminations or layers, or by winding coils in proper registration, for example, on a multi-layer, multi-pitch coil form.

Offset nulling system for computer disk drives

Abstract: An offset nulling system is provided for use in computer disk drives to identify and compensate for actuator head position offset errors attributable to dc offsets of the disk drive control circuitry, thereby obtaining improved head alignment wiht a designated track on a memory storage disk or the like The system includes a microcontroller adapted during a calibration mode to identify the position offset error and direction for selected tracks located respectively at radially inner and radially outer regions of the disk, and to adjust head position incrementally relative to those tracks to subsantially eliminate position offset error Thereafter, during a normal operation mode of the disk drive, the microcontroller functions at the conclusion of a track seek step to adjust the head through a position offset compensation value and direction derived by interpolation of the position offset compensation value and direction identified during the calibration mode, in accordance with the specific track address

Flexible, next-address generation microprogram sequencer

Abstract: A flexible, sequencer for providing next-address generation in the execution of a microprogram is described. The sequencer includes means for receiving an externally provided base address and an externally provided address offset value, a stack for storing return base address pointers, and means for storing a current program pointer counter address. The sequencer comprises means for selecting an address from one of a plurality of generated addresses and for providing the selected address as the next address in the execution of the microprogram, and means for generating the plurality of addresses including an address generation means selected from the group consisting of means for adding the address offset value with a stack stored return base address, means for adding the address offset value with the current program pointer counter address, means for selectively incrementing the selected address by one of a plurality of predetermined integral values, and means for selectively shifting the address offset value and for overlaying the external base address with the shifted address offset value, each means respectively generating one of the plurality of the generated addresses.

Skew detector for digital image processing system

Abstract: Each line in a frame of video data is organized into continuous runs of white pixels, and those runs having lengths below a given threshold are transformed to black pixels. The data is then organized into runs of black pixels, and the start position of the longest black pixel run is noted for each horizontal line. Skew angle is computed from the offset distance between the noted black run start positions of successive lines. The offset angle is computed from the mean of a set of offset distances, the set being large enough to minimize the RMS standard deviation of offset distances below a predetermined value. The set of successive black runs fall in a staircase pattern whenever there is a non-zero skew angle.

Allignment method for positioning textual and graphic objects

Abstract: In a computer system, an application program is able to specify the location of an object to be displayed relative to another object to be displayed by means of alignment points selected for each of the objects. The alignments points include the intersections of vertical lines through the left and right edges and center of an object and horizontal lines through top and bottom edges, center and baseline of a first line of text. An offset between the selected alignment points may be specified. The alignment points are defined independent of the content of the objects, and the operating system, in displaying the contents of each object, positions the object as specified by the alignments points and offset. Where an object is aligned relative to two anchor objects, the operating system may adjust the size of the aligned object.

Differential circuit with controllable offset

Abstract: In various analog applications, it is desirable to have a known offset voltage at the input of a comparator, operational amplifier, or other type of differential stage. For example, in an ISDN receiver, the use of a desired offset allows for discriminating between signals having different amplitudes. In the present technique, a reference current, derived from a reference voltage ( V ref ) and on-chip resistor (R1) is used to set the currents through two input transistors, typically MOS transistors. An offset resistor (RO) in the source lead of one of the transistors produces a voltage drop that sets the offset at an input of the differential stage. The voltage drop across RO is proportional to ( V ref X RO)/R1. Since RO and R1 are fabricated by the same process, their ratio is independent of temperature, process, etc. Therefore, a well-defined offset is obtained.

Liquid crystal display driving device

Abstract: PURPOSE: To prevent the constitution from increasing in size, the operation speed from decreasing, and the driving signal from having variance by averaging the offset voltage of a picture element signal voltage with an adjusting signal which reduces the difference between a reference signal and the mean signal obtained by averaging sample-held signals obtained by sampling and holding the reference signal. CONSTITUTION: A mean offset calculating circuit 23 calculates the mean signal by averaging the reference signal and ≥1 sample-held signals generated by sampling and holding the 1st reference signal A corresponding to respective picture elements. An adjusting signal generating circuit 27 compares the mean signal calculated by the mean offset calculating circuit 23 with the 1st reference signal A and generates the adjusting signal for reducing the difference between both signals. A driving adjusting circuit 21 adjusts the offset voltages of respective picture element signal voltages according to the adjusting signal generated by the adjusting signal generating circuit 27. Consequently, the increase in the size of the constitution, a decrease in the operation speed, and the variance of the driving signal are prevented. COPYRIGHT: (C)1990,JPO&Japio

Selective processing of a data stream based on font format

Abstract: The system and method of this invention processes a data stream based on the structure of a font file which can be varied by a user or application of the processing system. The font file not only contains the pel patterns for a range of graphical symbols, but it also contains the rules for interpreting a data stream having a particular syntax. The rules for interpreting a data stream are referred to as the processing model for the data stream. The structure of the font file contains an index array to the range of graphical symbols. Each byte in the data stream is used to generate an index into the index array. In each element of the index array there is a value and control bits. The control bits indicate whether the value is an offset to a graphical symbol or whether the value is a modifier. If the value is a modifier, it is used to increment the next sequential data byte in the data stream through the range of graphical symbols. The modifiers can be used recursively to access an unlimited number of graphical symbols.

Machining system based on inverse offset method.

Abstract: This report describes how to create an offset surface between any tool shapes and machining surface to a necessary level of accuracy in 3 axis machine tool. It is able to consider that the machining surface is constituted by many elements, which are cutting points. An offset surface between the tool shape and an element is able to define as a reversed tool shape with Z-direction. Accordingly, the offset surface of the machining surface may be regarded as an envelope which is obtained by set operation of offset surfaces for those elements. In order to execute these set operations by computer, a spatial array is employed as a memorizing area of the offset surface. And also in order to save memory capacity, a quad-tree data structure is employed.

A modified approach to two-level logic minimization

Abstract: A methodology in which it is not necessary to compute the entire offset is presented, that still provides a global picture. This scheme has been implemented in ESPRESSO with an interface to the multilevel minimization environment MIS. Initial results show that for functions for which the ratio of the size of the cover to the size of the don't care set is small, the new approach is much faster. The initial interest was to use this mainly in a multilevel logic synthesis system where the desired don't care sets are typically large. Some results in this environment are given, and the new scheme is compared with ESPRESSO. >

Method and apparatus for automatically calibrating the gain and offset of a time-shifted digitizing channel

Abstract: A circuit for automatically matching the gain and offset of a time-shifted digitizing channel in a data acquisition circuit which includes a reference digitizing channel, having a fixed voltage reference, and at least one time-shifted digitizing channel having components that are adjustable for gain and offset. Feedback is provided by examining the dynamic range and average value of a known input signal which is digitized, sent through the time-shifted digitizing channel and stored in memory. A microprocessor reads the stored data and, by separately varying the gain and offset parameters, computes optimal values for each parameter. Digital-to-analog converters (DAC's) allow the microprocessor to communicate with one fixed-gain variable-offset amplifier in the front end and with one fixed-gain variable-offset amplifier and one analog-to-digital converter (ADC) in each time-shifted digitizing channel. By controlling the offset of the amplifiers and the reference level of the ADC, precise matching of the gain and offset of the time-shifted digitizing channel with the gain and offset of the reference digitizing channel may be performed easily and inexpensively. The circuit may be extended to an arbitrary number of additional time-shifted digitizing channels and provides a comparatively simple, inexpensive way to automatically match the gain and offset of each time-shifted digitizing channel.

Offset compensation circuit

Abstract: An offset compensation circuit for compensating a DC offset which occurs in a circuit line including an A/D converter or an A/D and D/A converter in which not only the polarity bit of digital data but also information concerning the amplitude of an analog input signal are applied to an integrator to precisely compensate an offset voltage in a circuit line. The level of a proper offset compensation voltage is provided even when an input analog signal such as a music signal is absent, and when an A/D and D/A converter is provided which can perform both A/D conversion and D/A conversion the DC offset can be precisely compensated shortly after the change of the mode from D/A conversion to A/D conversion.

Continuous mode auto-zero offset amplifier or integrator

Abstract: An error signal, i.e., offset, noise or drift, is sampled in an input capacitor at an error sampling interval and held during the amplification interval. During the amplification interval, the signal is amplified offset-free. The circuit has two paths which operate alternately in such a way that the signal path is never interrupted, except for very brief intervals. Each of the two paths includes an operational amplifier, and the offset voltages of the two operational amplifiers are cancelled out automatically.

Bathymetry using computational algorithm field and background of the invention

Abstract: A method and apparatus steers the returning beams of a receiver in a swath bathymetric system to an actual target based on prior steering angle information for the target and using an algorithm which demonstrates a linear relationship between the phase of the return beam and the steering angle therefor. The receiver comprises a plurality of transducing elements which each emit a signal. The array is divided into two groups of elements which are processed and combined to form beams for each group which are steered to the known steering angle for the target. Beams are then steered to a slightly offset angle to produce an offset beam. Using an equation to define each return beam according to phase and error between prior known and actual steering angles for the target, the error value can be reduced to zero to provide an accurate measurement of the actual steering angle for the target.

Method of tiling a figure in graphics rendering system

Abstract: Method of drawing a convex geometric figure to framebuffer storage sequentially addressable as a plurality of update arrays of determined origins which tile the framebuffer An array comprises pixel storage sites, each specifiable by an offset from array origin, and concurrently updatable A figure is specified as a set of directed lines, whose segments between mutual intersections comprise the figure boundary, perambulating the boundary in a single sense The figure is tiled by a subset of the update arrays A first array is accessed Tests are performed to find whether the figure extends to arrays above or below the accessed array; if so the array address is stored and marked for either or both extensions In one embodiment, a test is performed for left extension, and the steps are repeated until no further left extension is found; returning to the initial array, the steps are repeated for right extension to complete the horizontal subset The array marked for either up or down extension is next accessed and the steps are repeated with respect to the indicated vertically adjacent array until no further extension is found in that vertical direction; the steps are repeated for the other vertical direction The figure has been tiled The extension test tests, with respect to the directed lines and a pair of sample pixels adjacent to the questionable array, for sidedness of each sample pixel with respect to each line

Method and means for path offsets memorization and recall in a manipulator

Abstract: A method and means for memorizing path deviations of a manipulator arm, and recalling the same deviations to adjust succeeding passes. During the seam-tracking pass, any feature or sensor system can be used which will cause the manipulator supported tool to deviate from the programmed path of travel. Offsets generated during the initial seam-tracking paths are memorized and thereafter recalled so that the manipulator arm can perform subsequent passes along the seam with the seam-track function off. While seam-tracking, the offsets are automatically memorized at distinct preprogrammed offset distance intervals. Each offset is placed sequentially in a memory data table. The offsets are recalled during a subsequent pass at each offset distance interval at which they were memorized so that the subsequent pass has the same deviations as the initial seam-tracked pass. Subsequent passes can be executed in the same direction as the initial seam-tracking pass, or in the opposite direction. In the first instance, offsets are recalled from the memory data table in a first-in, first-out basis. In the second instance, the offsets are recalled in a first-in, last-out basis.

Method for bin, moveout correction and stack of offset vertical seismic profile data in media with dip

Abstract: Seismic energy is generated at a multiplicity of source offsets from a borehole and offset VSP data is collected by an acoustic detector at a multiplicity of geophone depths for each source offset. The recorded data is sorted into Zero Source-Receiver (ZSR), common reflection point bins. Data from each offset VSP, ZSR common reflection point gather are dynamically moveout corrected with data adaptive parameters including reduced direct arrival times, dip, borehole deviation and stacking velocities. The moveout corrected VSP data are then stacked.

Network analyzer calibration using offset shorts

Abstract: Microwave network analyzer accuracy enhancement by offset shorts is investigated. Usable calibration bandwidth and accuracy limitations are determined by applying a previously published model by L.A. Glasser (1978) to the case of a reference short and two offset shorts. Data necessary to emulate the HP 8510 scalar network analyzer are derived and used in the model to provide realistic projections. Convenient techniques for optimizing experimental accuracy and for obtaining an estimate of the uncertainty in actual short circuit and offset short calibration standards are also presented. >

System and process for generating a tool path offset

Abstract: A system and method of tool path processing is taught which offsets a tool path from a given geometric sequence, avoiding tool interference and accounting for coincident tool paths. It guides a numerically-controlled machine tool in the manufacturing process. In accordance with the present invention, a computer-aided-manufacturing system defines or allows definition of a pattern to be machined by a tool having an offset, analyzes the pattern for points of intersection, breaks down the pattern into contiguous segments between points of intersection, structures a list of the segments, ordered between intersection points, defines tool path chains, responsive to the list; validates the tool path chains to define valid tool paths, and, guides the movement of the tool along a valid tool path.

Circuit for driving dot matrix printers with individually positioned print elements

Abstract: A circuit for reorganizing a bit mapped source image into a print image is disclosed. The circuit can be used to simultaneously actuate individually located print elements (36) of a printer. Offset values corresponding to the individual positions of each print element are stored in an offset memory (52). The offset values are each added to a base address to generate an addressing mask for accessing desired bits of a source image (81) stored in a source image memory (80).

System for binary encoding a picture

Abstract: Methods and apparatus for encoding an image of an object into a binary signal involve the measurement of a preliminary view of the object in order to extract peak optical density information. That peak optical density information is then used to set the thresholds used for comparisons with video signals of the object to encode those video signals as binary signals. The methods and apparatus are also able to detect the offset of the object in the field of view from a standard position and to adjust the images of the objects being measured so that a predetermined "window" of the object is always being viewed.

Large‐offset approximations in the modified cagniard method for computing synthetic seismograms: a survey1

Abstract: Large horizontal offset and large vertical offset approximations in the modified Cagniard method for computing synthetic seismograms in a horizontally layered model of the earth are derived They apply to each of the generalized-ray constituents into which the seismic wave motion is decomposed For the results applying to large horizontal offset, which are known in the seismological literature, a simplified derivation is given The results for large vertical offset, which are of particular interest to vertical seismic profiling, are new The use of the large-offset approximations, both horizontal and vertical, leads to a considerable reduction in computation time for synthetic seismograms compared with the full three-dimensional version of the modified Cagniard method

Image Focusing in Space and Time

Abstract: : The integral form of the instrument transmission function for a one-dimensional pixel in a two-dimensional optical system is presented. The integral is solved explicitly in the paraxial ray approximation for a single spatial Fourier component of a Lambertian object. The difference between signals from adjacent pixels is derived. It is shown to have zero derivative with respect to focusing error when the focusing error is zero, i.e., it is a weak source of range-from-focus information. Describing the instantaneous focusing error as the sum of a fixed offset and a time-domain sinusoidal dither, the power spectrum of the signal from each individual pixel is shown to large first and second harmonic terms for physically reasonable values of the parameters. The first harmonic signal is proportional to the product of the dither amplitude and the offset. The second harmonic signal is proportional to the square of the dither amplitude and is independent of offset. The two coefficients are identical except for an integral numerical factor. It is suggested that the ratio of second harmonic to first harmonic signals is thus potentially a powerful measure of offset, i.e., of focusing error in the limit of zero dither, and thus of range-from-focus pixel-by-pixel. Extending the model to three dimensions, removing the approximations, extending the model to natural scenes, and verifying and implementing the results experimentally are outlined briefly. Keywords: Image processing; Pixels(picture elements). (JHD)

Track access control system for magnetic disk apparatus

Abstract: An improved track access control system for a magnetic disk apparatus connectable to a variety of host controllers without any change thereto, and capable of an offset correction. A control unit (4) in the disk apparatus controlling a moving unit (3) to access a magnetic head (2) at a desired track on the magnetic disk in response to a seek command from a host con­troller and using an offset correction value which is previously obtained by accessing the magnetic head at a track storing the fine positioning information, and carrying out an offset correction, includes a timer (TM) to which a time to be offset-updated within a predeter­mined timing is set. The control unit makes an offset correction value invalid in response to the time out of the timer, and when a seek command from the host con­troller in response to the offset invalidity is issued within a predetermined time, the control unit carries out an offset correction in response to the seek com­mand, and executes the seek command, or inhibits an output of an index signal, carries out an offset correc­tion at a previously given track from the host con­troller, and thereafter, permits an output of the index signal. The control unit sets the time for updating the offset correction to the timer.