Abstract: A system is disclosed for the editing of electronic documents wherein the hardcopy of an original document is scanned into digital form to provide an electronic version of the document. The original document is then placed on an x-y digitizer with the position of the original document being correlated with the electronic version of the document in order to provide corresponding scaling, rotation and offset of the documents. The original document is then edited with a digitizer pen that marks the original document while at the same time converting the handwritten edit into digital form. The digitized edit is then combined with the electronic version of the document to produce an edited electronic document that can be displayed on a local and/or remote computer screen or the like. The system is useful in such applications as teleconferencing, where it is desired to edit the electronic version of a document that is displayed at multiple locations.

Abstract: A digitizing tablet is disclosed in which two sets of circuitous conductive lines form grids each connected at one end to a surrounding conductive loop. All outputs are measured from the conductive loop as a multiplexor sequentially grounds the grids one at a time. The outputs are fed through linear spatial filters which are used to produce intermediate signals which are in turn combined to arrive at raw position signals for a position indicating coil located over the work surface. Separate sets of linear spatial filters may be used to produce two raw position signals differently responsive to tilt which can then be combined to arrive at a true position signal insensitive to tilt.

Abstract: A pen plotter employs a cable-driven carriage which carries the writing pen and includes a pen-lift mechanism. A shifting idler pulley system located at one side of the plotter returns a pair of drive cables from the opposite side of the carriage to a rotatable drive drum located on the opposite side. The idler pulleys are shiftable equally and in opposite directions toward and away from the pen carriage. One cable is connected to the carriage by being tensively trained about a pen-lift mechanism drive wheel on the carriage. Shifting the idler pulleys causes said drive wheel to rotate without affecting the lateral position of the pen carriage and, therefore, the shifter mechanism independently controls the up/down motion of the writing pen. One drive cable, therefore, accomplishes the functions of both pen carriage movement and writing pen up/down motion control.

Abstract: A two dimensional digitizing system comprises two systems at right angles to each other, comprising two conducting grid structures each having three terminals A, B, and C, with the grid conductors running parallel to the X axis in one system and the Y axis in the other, and a cursor coil. When the cursor coil is excited with an alternating current, voltages e.sub.ab, e.sub.bc and e.sub.ca are induced between the terminal pairs AB, BC and CA respectively, whose amplitudes are functions of the position of the cursor coil relative to a cartesian co-ordinate system defined by said X and Y axes.The voltages e.sub.ab, e.sub.bc and e.sub.ca from each system are phase shifted and summed to provide two single signals e.sub.x and e.sub.y whose phase shift from a reference signal derived from the cursor coil excitation is a linear function of cursor coil displacement along the X and Y axis respectively.The phase shifting is accomplished by a passive network connected to the three grid winding terminals.

Abstract: A two dimensional digitizing system comprising two systems at right angles, each system having at least two conducting grid systems. Each grid system is comprised of a number of windings with a pitch distance D and an equal number of windings with a pitch distance D+.DELTA.d, where .DELTA.d is a small increment in distance. These windings produce a number of voltages whose amplitude varies cyclically as an AC excited cursor coil is moved in a direction at right angles to the conductors in a plane parallel to the plane of the conductors. Active or passive networks are provided for converting the grid voltages into signals whose phase with reference to the cursor coil excitation current varies linearly with cursor position. These signals are cyclic in nature going through a phase displacement of 360 degrees when the cursor moves through distance D in the case of one grid winding and a distance D+.DELTA.d in the case of the other grid winding.