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| Number | Title | Issue Date |
| 4723056 | Coordinate position digitizing system A coordinate position digitizing system incorporates apparatus for detecting the X and Y positions of a voltage detecting device relative to a position determining plate employing apparatus for generating data corresponding to the X and Y positions of sai... | 02/02/1988 |
| 4710595 | Coordinate input device A coordinate input device is provided of the type comprising main loops made of conductors embedded parallelly in an input plane, a compensating loop disposed in the vicinity of the common wire of the main loops, switching elements for successively sendin... | 12/01/1987 |
| 4686331 | Digitizing method and apparatus for compensating cursor of stylus velocity errors A digitizer measuring abscissas and ordinates at separate times compensates these coordinates for errors created by cursor or stylus motion during the digitizing process. At the highest level of operation this is achieved by altering the coordinate measur... | 08/11/1987 |
| 4679159 | Automatic adjustment method of tracer head Manual zero adjustment of a tracer head and adjustment of differential amplifiers for the tracer head are eliminated by a step of storing the outputs of differential amplifier circuits as zero-point offset amounts while maintaining the tracer head in a no... | 07/07/1987 |
| 4679241 | Method and apparatus for correcting x-y position measurements A two-dimensional coordinate measuring pad for use, for example, to recognize handwriting. A high resistivity sheet is bounded by a lower resistivity border connected to a switched voltage source to cause a current to flow first in one direction and then ... | 07/07/1987 |
| 4650926 | Electrographic system and method An electrographic system and method having a control which carries out correction for graphic surface non-linearities. The control employs a procedure wherein a correction look-up table is developed as part of the manufacture of the device wherein output ... | 03/17/1987 |
| 4642422 | Calibration of a scanning light interrupt type of data input interface Correlation of light beam movement with electrical timing in a light beam interrupt data input interface device is provided by determining the magnitude of an angular difference between the electrical system and a line through the scanning axis for use as... | 02/10/1987 |
| 4577057 | Digitizing tablet system having stylus tilt correction A digitizing tablet system of the type including a tablet, a stylus and associated electronics which is constructed to correct for tilt errors when the stylus axis is tilted relative to the tablet is disclosed. The tablet includes a housing having a recta... | 03/18/1986 |
| 4575581 | Digitizer and position encoders and calibration system for same Digitizer incorporates two novel position encoders. One position encoder comprises means for periodic spatial calibration against an accurate pattern of reference marks, thereby improving accuracy to the limit of resolution. Optionally, it also includes t... | 03/11/1986 |
| 4514688 | Digital tablet system with calibration means An improved position determination device utilizes an energized movable pointer which is inductively coupled to a grid of spaced parallel electrical conductors for each coordinate direction. The termini of the spaced conductors of each grid are traversed ... | 04/30/1985 |
| 4477877 | Coordinate determining device A coordinate determining device comprised of a tablet having a plurality of sensing lines disposed thereon, and a magnetic field generator positionable relative to the sensing lines for indicating the coordinates of the magnetic field generator position. ... | 10/16/1984 |
| 4181952 | Method and means for minimizing error between the manual digitizing of points and the actual location of said points on an _electronic data entry surface There is disclosed a method and means for increasing the positional accuracy of operator controlled cursors engaged in the digitized encoding of graphic information such as line drawings. The method steps comprise those of digitizing the instantaneous con... | 01/01/1980 |
| 4018989 | Position coordinate determination device A position coordinate determination device employing duodatum digitizations for each coordinate of a pair of respective coordinates and a ratiometric proportionality calculation for calculating a corrected coordinate digitization value in each measured co... | 04/19/1977 |
| 4009339 | Device providing sensible output indicating receipt of data by computer The device, which may be connected either directly to the computer itself or which may form a part of a remotely located input/output station, includes electronic signal generation circuits for generating a signal indicative of the receipt of data being i... | 02/22/1977 |
| 4009338 | Tablet with improved pen height compensation An improved operation is provided for a graphic tablet of the type in which a pen is capacitively coupled to sets of X dimension wires and Y dimension wires that are digitally activated to produce a pen signal that signifies the position of the pen on the... | 02/22/1977 |
