Abstract: A national broadband network is based on fiber optic technology and scaled to cover a wide area, such as the contiguous lower United States. The network provides a high data rate interface for each subscriber and supports all the functions of the current telephone, Internet, and cable TV networks, with sufficient excess capacity to support future applications. Signals from several thousand subscribers are multiplexed on a single fiber pair connected to an intelligent switching center. Telephone central offices (COs) become multiplexing centers rather than switching centers, and the number of switching centers required to cover the nation is greatly reduced. Approximately 500 switching centers are interconnected by an optical backbone. Physical layer connections are established through the backbone between each pair of switching centers. Multiple ATM and/or STM connections are carried within each of these physical layer connections.

Abstract: An ion-sensitive sensor has an active layer of silicon with source and drain diffusion regions of a field-effect transistor formed therein, patterned layers of silicon oxide and metal on one side of the active silicon layer, and a layer of insulative support material on the metal and silicon oxide layers. A continuous layer of silicon oxide on the other side of the active silicon layer has an exposed surface in the region of the field-effect transistor so that surface charge is formed in the exposed area of the continuous silicon oxide layer when placed in contact with an electrolyte solution. The surface charge induces a channel in the undiffused channel region between the source and drain regions, enabling the flow of current between source and drain contacts under proper bias conditions.

Abstract: A linear position encoder is provided which is not affected by ambient light, smoke, moisture, particulate matter, and also not affected by electrical interference such as may be caused by stray fields or permanent magnets or magnetic particles. The encoder comprises a linear scale having an excitation loop disposed along the length of the scale and having electrical terminals preferably disposed at one end of the scale. An alternating current is applied to the excitation loop to create an alternating magnetic field. At least one periodic conductive pattern is provided on an outer side of the excitation loop. The periodic pattern has electrical terminals preferably at the same end of the scale as the terminals of the excitation loop. A sensor is provided on a small printed circuit card that is movable in relation to the scale. The card has a pickup loop which receives energy coupled from the scale excitation loop and which induces current in the periodic pattern.

Abstract: A software development tool utilizes an intermediate object modeling language. The structure of the desired program is first described graphically by generating rule diagrams, state diagrams, and object diagrams such as user interface diagrams, event diagrams and other object diagrams. The development tool employs the diagrams to generate a working model of the program expressed in the object modeling language. The working model of the program can be executed without lengthy compiling, and hence program behavior can be quickly observed and tested. Further, the behavior of the working model can be quickly and easily changed by modifying the diagrams until the desired result is achieved. Source code is then generated from the object modeling language and compiled to create the final program.

Abstract: A communications switch that connects together multiple communicating nodes such that optical signals flow transparently through the switch. Each node is connected to the switch by an optical cable containing input and output optical fibers, with each fiber containing optical signals at multiple wavelengths. For each multi-fiber cable, an optical beam is formed containing the input signals from that cable. Within each beam, the different input signals are spatially adjacent to each other. The signals within a particular beam are spatially gated to form multiple beam segments. Each of these beam segments is spatially shifted to a different output, where it is combined with beam segments obtained from the inputs from other cables. Signals from multiple beam segments are concentrated onto the output fibers of each multi-fiber cable.

Abstract: A magnetic encoder is disclosed that provides a uniform magnetic field which is time modulated at a carrier frequency and space modulated by a repetitive pattern of eddy-current conducting lands that move with variable motion. The time modulation is provided by driving an electrical coil in a resonant tank circuit. The space modulation provides areas of higher and lower magnetic field intensity which change in correspondence with the motion of the conducting lands. The intensity of the varying magnetic field is detected by a series connected pair of stationary coils that are positioned orthogonal to both the direction of the changing magnetic field and the direction of the motion of the conducting lands. The pair of stationary coils yield a differential electrical signal that is representative of the motion of the conducting lands.

Abstract: A light beam encoder for measuring absolute distance over a linear path with an accuracy of at least that provided by incremental optical encoders, but over longer ranges than can readily be achieved with optical linear encoders due to the difficulty of providing a sufficiently long optical scale with the requisite accuracy and resolution. The resolution provided by the light beam encoder can be approximately 1-10 microns. A high frequency amplitude modulated light beam is reflected by a reflector disposed at the distance to be measured, and the phase lag of the reflected light beam is determined to provide an absolute measure of the distance. The encoder mixes a local oscillator signal generated by a phase locked loop with both a reference oscillator signal and the distance signal. Thus, the heterodyne mixers provide two low frequency signals preserving the phase lag between the two optical signals.

Abstract: An edge-type printhead and method of fabricating the same, eliminates the need for precision grinding, lapping, and polishing of a substrate, avoids the need for precision etching of electrode patterns, avoids the use of highly refined etchable thick film pastes, and avoids the need for precision glaze application in the construction thereof. Contact pads are provided on the printhead writing surface. The contact pads facilitate accurately and inexpensively delineated resistor lengths, provide resistor current spreading for full dot width printing and control resistor row straightness. Contact pads permit the use of standard wet or chemical etching with wide spacing between electrodes while facilitating full width printed dots with narrow spacing. The contact pads are applied to the writing edge after the edge-type substrate is laminated, sectioned and the writing surface is polished.

Abstract: A true edge thermal printhead and method of fabrication wherein the printhead infrastructure is formed by thick film techniques and the individual laminations are formed in a predetermined order. The printhead infrastructure includes a dielectric substrate, a common electrode layer, a high temperature glaze, an electrode pattern, a low temperature glaze and a plurality of resistive heating elements formed on the edge of the infrastructure and interconnected to the electrode pattern and the common electrode layer. The common electrode layer is a unitary sheet of refractory conductive material that is compatible with the high firing temperatures required for the high temperature glaze, and includes multiple ground taps. The fine image electrode pattern is compatible with the reduced firing temperature of the low temperature glaze such that gold pastes may be efficaciously utilized in the formation of the electrode pattern.

Abstract: A digital resolver is provided that accepts an analog representation of an angular or linear displacement within a reticle modulation cycle of a rotatable or translatable member, and provides a highly accurate output digital representation of the displacement within the cycle, even during rapid movement of the member. An encoder cooperative with the interpolator receives an analog signal that represents the displacement, and yields a pair of quadrature-phased sine wave signals accordingly. These signals are provided to the interpolator, wherein each is multiplied by a stored digital representation of a trigonometric function of the output digital signal. The resulting products are then added so as to provide an error signal which is used to drive a digital control loop, such that a digital output signal is provided that represents displacement within a reticle cycle.

Abstract: A thermal print head is provided having a substrate with an arcuate edge ground to a selected radius upon which a layer of glaze is deposited and precision ground. Resistive film is patterned onto the glaze and conductive film is applied in electrical connection therewith.

Abstract: A modular thermal print head and method of fabricating same including a first member having at least one surface on which is arranged an array of electrodes, and a second member mounted in spaced relationship to the first member and having at least one surface on which is disposed a single conductor element. A thermal printing element having an array of electrically resistive members terminated at one end by conductor pads arranged in an array, and proximate a second end to a common conductive member is provided. The thermal printing element is disposed between the first and second members with its array of conductor pads in contact with the array of electrodes on the first member, and its common conductive member in contact with the single conductor element on the second member. Selected portions of the thermal printing element may be energized to produce thermal printing energy.

Abstract: A method for fabricating a nozzle plate having three dimensional features is provided. On a conductive surface, a plurality of non-conductive masked areas of selected dimensions are formed at locations corresponding to the locations of the holes of the desired nozzle plate. A layer of a first metal is electroformed onto the conductive surface until the layer of the first metal overgrows the masked areas by a selected amount. A first layer of a second metal is then electroformed over the layer of the first metal until a plurality of holes having diameters corresponding to the diameters of the holes of the desired nozzle plate are formedin the first layer of the second metal. Depressions formed in the first and second metal layers during the plating process are filled with a planarizing filler. A second layer of the second metal is then electroformed onto the first layer of the second metal to form a plurality of holes in registration with the depressions.

Abstract: An absolute encoder providing a multi-bit output binary code indicative of the position of a rotary or linear scale. The encoder employs a code track, which contains a serial code, and a clock track. The encoder may be either rotary or linear, and may be implemented optically, magnetically, inductively, capacitatively or by any other binary sensing technique.

Abstract: A compensation system for a position encoder which automatically compensates for scale and other similar errors along the entire path of relative motion. The phase of the encoder signals is altered by a small amount for each small increment of relative motion to provide encoder signals compensated for the scale error. The phase correction is added to or substracted from the phase of the encoder signals depending upon the sense of relative motion.

Abstract: An absolute encoder providing a multi-bit output binary code indicative of the position of a rotary or linear scale. The encoder employs a code track, which contains a serial code, and a clock track. The encoder may be either rotary or linear, and may be implemented optically, magnetically, inductively, capacitatively or by any other binary sensing technique.

Abstract: An electrostatic or thermal printhead and method of fabrication is provided in which dielectric material is disposed in a row of spaced depressions or in a single recess along the upper surface of an edge of a dielectric-coated conductive sheet. Electrodes are disposed along the edge of the sheet over the dielectric material and terminate at associated conductive pads or printhead circuitry on the sheet. In one embodiment, the edge is trimmed and left bare to form an inexpensive electrostatic printhead. In an alternative embodiment, resistive material is disposed over the edge to connect the electrodes to the conductive sheet to form an inexpensive thermal printhead.

Abstract: An electrostatic or thermal printhead and method of fabrication is provided in which dielectric material is disposed in a row of spaced depressions or in a single recess along the upper surface of an edge of a dielectric-coated conductive sheet. Electrodes are disposed along the edge of the sheet over the dielectric material and terminate at associated conductive pads or printhead circuitry on the sheet. In one embodiment, the edge is trimmed and left bare to form an inexpensive electrostatic printhead. In an alternate embodiment, resistive material is disposed over the edge to connect the electrodes to the conductive sheet to form an inexpensive thermal printhead.

Abstract: An orifice plate and method of fabrication are provided in which the plate is constructed of two electroformed layers of metal. Onto a conductive mandrel a first layer of a first metal is electroformed to provide a support layer having a selected hole pattern. The first layer is then plated with a thick layer of a second metal and removed from the conductive mandrel exposing the bottom surface of the first layer. On the exposed bottom surface, a thin second layer of the first metal is electroformed to produce a pattern of holes of a selected smaller cross section in cooperation with the hole pattern of the first layer of the first metal. The thick layer of the second metal is then etched away, producing a thin metal orifice plate having a pattern of small holes of a selected cross section and supported between the holes by an additional, thicker layer of the same metal.

Abstract: A high-resolution thermal printhead and method of fabrication is provided. The printhead is of laminated construction in which densely packed circuitry required to achieve high resolution print is separated from other circuitry not requiring such dense packing. Therefore, the expensive fabrication processes required to produce the fine, high-resolution circuitry are limited to such circuitry, while less expensive fabrication processes are used to manufacture all other portions of the printhead.