Abstract: Improved image enhancement methods are disclosed which may be performed on conventional video processing systems. These methods operate in real time to improve the appearance of images as perceived by the human eye, and/or to render these images more suitable for computer analysis. A first preferred embodiment enhances color images without degrading the fidelity of the image. A second preferred embodiment enhances scanned gray-level document images by decreasing the blurring of the image and increasing the contrast between light and dark regions of the image.

Abstract: A method for electronic communication using wide area network (WAN) storage and signalling capabilities. The method and apparatus provides for deposit of a message in message stores in the WAN, storage of the message such that the message is uniformly accessible throughout the WAN and notifying the recipient of the message of the availability and address of the message in the message stores in the WAN so that he can access the message.

Abstract: A private base station location register supports the registering of multiple mobile stations at a private base station and provides control information for enabling a personalized call delivery feature at the private base station for each registered mobile station. When registration of a mobile station with a private base station is performed, the private base station location register receives mobile station information from a private base station along with assignment of a local unique address for each one of the multiple mobile stations registering with the private base station. When the private base station receives an incoming call for a particular one of the mobile stations, this local unique address associated with the particular station is provided by the base station location register as part of the incoming call information also received by the base station thereby allowing the base station to distinctively alert the particular mobile station.

Abstract: A cordless telephone arranged for operation in a frequency hopping system quickly establishes communications between a base unit and an associated handset unit in the telephone. Synchronization between the base unit and the handset unit is achieved through a process in which first the base unit sends a start hopping message contiguously for a specific number of frames or time slots. The handset unit, in turn, responds by sending a staff hopping acknowledge message to the base unit in a frame each time it receives the start hopping message in a frame. In response to the handset unit sending the start hopping acknowledge message, the base unit sends to the handset unit an acknowledge hopping message, also for a specific number of frames. If either the base unit or handset unit fails to receive a message in a specific frame, the synchronization process advantageously continues since each one of the messages contained in the specific number of frames linearly decreases in value with each succeeding frame.

Abstract: Signal energy in an installed optical fiber is extracted without using a physical connector, by an improved process in which the fiber is bent to within a prescribed range of angles, then controllably heated, and thereafter controllably cooled. The resulting structure exhibits relatively low permanent stress. A fiber end conventionally placed at the bend point receives unusually useful amounts of optical signal which can be routed to optical branch circuits in, for example, a building or a LAN.

Abstract: A method and apparatus for reducing correlated errors in subband coding systems with quantizers is disclosed. A subband coding system comprises a plurality of subband analysis filters to divide the frequency spectrum of the input signal into subbands, individual subband quantizers for coding each subband by a preselected number of quantization levels, corresponding subband decoders and subband synthesis filters. The transfer function of each of the subband synthesis filters is advantageously determined based on the transfer functions of the subband analysis filters as well as on the characteristics of the quantizer used to code the corresponding subband. Specifically, the synthesis filter transfer functions may be based on a perfect reconstruction filter bank or a quadrature mirror filter bank, as well as on the gain factors of a gain plus additive noise linear model for the Lloyd-Max quantizers used to code the corresponding subbands.

Abstract: Disclosed is an optical fiber distribution apparatus with slide-out trays including optical connectors and splice trays mounted thereon. Each tray has a hinged protective cover and a front portion which drops down to provide access to the connectors. The splice tray is mounted on a platform elevated from the tray so that fibers coming into the tray can be stored in the gap formed thereby.

Abstract: A microwave directional coupler comprises a dielectric coupler board, elongate metallic strip conductors deposited on front and back surfaces of the board and having respective central portions electrically broadside coupled with each other through the board, and respective right and left hand lead portions terminating in ports at the bottom of the board. Metallic ground plane regions cooperate with those strip conductors to form corresponding microwave transmission lines comprising respective signal conductors provided by said strip conductors and respective grounded conductors provided by said regions. The ground plane regions are in the form of expanses of metallic layers deposited on the same surfaces of the board as are such strip conductors. Ground plane regions on opposite sides of the board are electrically connected by plated-through holes passing through the board.

Abstract: A method for use in a telecommunications system in which a call sequencing facility allows a caller who is trying to reach a called subscriber to be routed to each of a sequence of telephone numbers specified by the subscriber, even though a call placed to one such telephone number is answered.

Abstract: When a telephone caller charges a call to a commercial credit card an announcement which includes the name of the credit card issuer is supplied to the caller after the validation of the credit card. In a preferred embodiment, the issuer of the commercial credit card is identified, for purposes of announcing its name, by examining the prefix code of a credit card number supplied by the calling party. Also, in the preferred embodiment, not only the issuer of the commercial credit card but also the name of the telephone carder is supplied as part of the announcement given prior to connecting the calling station to the called station after validation of the credit card. An illustrative such announcement is "Thank you for using AT&T and for charging this call to your American Express card".

Abstract: A data converter is disclosed that includes a multiplier for multiplying digital signal samples by a gain factor to produce multiplied digital samples. The multiplier can either be bypassed or a dither signal can be introduced in the multiplication operation. A multiplexer responsive to a select input selectively provides either the digital signal samples or the multiplied digital signal samples as the output of the multiplexer.

Abstract: A model-based printing method and system for generating halftone output images corresponding to gray-scale-coded input signals. Models for individual two-level (e.g., black on white) printer types allow predicted printer error signals to be generated which can be used to modify the gray-scale coded signals in such manner as to produce binary signals which, when applied to the printer, create halftone images of enhanced quality. In an alternative embodiment binary signals are selected which minimize an error function based on the difference between (i) a predicted perceived image corresponding to the gray scale inputs as filtered by an eye-model filter and (ii) the halftone image resulting from filtering of the binary sequence by a filter modeling the printer followed by the eye-model filter.

Abstract: A modem, capable of simultaneously coupling voice and data signals, connects local digital terminal equipment (DTE) and a local telephone to a communications link. To prevent the local DTE from responding to a communications containing only voice signals, the local DTE is notified of an incoming communication only after detection of calling tone signals on the communications link. Such signals indicate a remote DTE desires to establish a data communications path with the local DTE. This operation advantageously prevents the modem from transmitting an annoying answer tone to a calling party.

Abstract: Nodal outputs are discretized to values of S2.sup.n where n is an integer and S is equal to +1 or -1. During forward propagation, this offers the advantage of forming a product of a nodal output and a weight using a simple shift operation rather than a multiply operation. Replacing multiply operations with shift operations through out a neural network improves response times and permits building larger networks that have broader applicability. Training is also improved by increasing the efficiency of backward propagation. The multiplications involved in backward propagation are reduced To shift operations by discretizing the errors associated with each node so that they are represented as 2.sup.n where n is an integer and S is equal to +1 or -1.

Abstract: A testing system for stressing assembled circuit boards well beyond normal operational limits with respect to mechanical vibration, supply voltage cycling, and temperature cycling. The combination of these three elements of stressing results in each of the three elements accelerating the effects of the other two elements. The circuit boards are transferred between a cold bath of inert liquid and a hot bath of inert liquid while power voltages are applied for short periods of time at voltages which exceed the normal voltages of the devices and vibrations are introduced into the inert liquid. The vibrations scan a broad range of frequencies thus accelerating the effect of the hot bath. In particular, in the hot bath, the use of ultrasonic frequency greatly accelerates the speed at which components are induced to absorb heat. The vibrations allow the detection of potential failures in the wire bonding of integrated circuits.

Abstract: An integrated circuit fabrication process for creating field oxide regions in a substrate is disclosed. In the process, masking layers of oxide, nitride and deposited silicon dioxide are formed on the substrate. A pattern that defines the field oxide regions in the substrate is introduced into the substrate through these masking layers. The field oxide region is bordered by steep sidewalls in a portion of the substrate and the masking layers overlying the substrate. A thin layer of oxide is grown on the exposed portion of the substrate, and a conformal second layer of nitride followed by a conformal layer of a polycrystalline material are formed over the substrate/mask structure. The polycrystalline layer is selectively removed, so that the only portion of the polycrystalline material that remains on the structure is the portion covering the sidewalls.