Abstract: Apparatus and a method of implementing a notification and hold service in a telephone network is disclosed. A calling telecommunications device is placed on hold by the called telecommunications device, and signals an auxiliary computer system through a network switch that the calling telecommunications device is to be disconnected from the called telecommunications device. The calling telecommunications device is notified at a later time that the called telecommunications device is no longer on hold. In another embodiment of the invention, the calling telecommunications device is connected to customer premise equipment which notifies that calling telecommunications device that the called telecommunications device is no longer on hold.

Abstract: A frequency hopping synthesizer is constructed from two FET-based multiplier circuits each responsive to a carrier input signal and a modulation signal to produce respective output signals which are in-phase combined to provide a frequency-shifted signal. The multiplier circuits each comprise two dual-gate field effect transistor (FET) amplifiers which are electrically balanced to suppress unmodulated carrier components so that only the modulated carrier signal appears. The respective carrier input signals and modulation signals are in quadrature phase relationship. A direct digital synthesizer controllably generates signal components which serve as the modulation signals for the multiplier circuits.

Abstract: A system and method for controlling access to a shared channel for cell transmission in a shared medium network, wherein the shared medium distribution portion of said network extends from a node to a plurality of terminals within a community, having a tree-and-branch bus topology, has a downstream broadcast channel from said node to all terminals on said distribution network; a shared upstream channel from all of said terminals to said node; and a network controller at said node for central control of access of media transmissions from said terminals over said upstream channel. Media access control protocols reside in said controller and in said terminals. An asynchronous transmission mode (ATM) network element with said controller has ATM shared channel protocols to provide dynamic bandwidth allocation of said upstream channel. The system grants access to said shared upstream channel to any of said terminals utilizing a plurality of multiplexing modes of operation.

Abstract: An optical amplifier is used as a frequency-selective high-gain element in a subcarrier-multiplexed fiber optic transmission system. A high-speed diode laser optical transmitter is modulated by a plurality of independent information channels that are carried on separate, appropriately spaced carrier frequencies. An optical receiver, coupled to the transmitter by way of an optical fiber, includes a narrow-bandpass semiconductor laser optical amplifier having a gain bandwidth smaller than wavelength distances between adjacent ones of the carrier frequencies, a photodetector coupled to the output of the amplifier, and polarization controlling means coupled to the fiber in front of the optical amplifier for maximizing gain in the optical amplifier.

Abstract: A means of power control on the reverse link of a CDMA network is disclosed. Specifically, the forward link from the base station to the subscriber unit is used to direct the subscriber unit to modify the output power radiated. The forward link consists of the forward packet data channel and the forward channel control channel. The forward packet data channel carriers the informational data to the subscriber unit, and the forward packet control channel includes carries of a power control setting. The forward channel is bi-phase modulated with the forward packet data channel transmitted in-phase and the forward packet control channel transmitted in quadrature.

Abstract: Apparatus is disclosed which is advantageously used in local area, metropolitan-area, and wide-area networks using a dual bus architecture, and more particularly to a dual bus network design having significantly increased distance before termination or regeneration of the optical signal, and using wavelength division multiplexing (WDM) at one optical wavelength to transmit data over the bus and a second optical wavelength to transmit a clock signal and a CATV video signal.

Abstract: Subcarrier multiplexed acknowledgment tones are used for contention recovery in multiple-access WDM networks with basedband data packets and subcarrier multiplexed control headers. Upon receiving a data message from another node, the receiving node sends a subcarrier acknowledgement tone to the transmitter thus informing the transmitting node that the message has been received. The thoughput of the network is significantly improved. In an alternative embodiment, an acknowledgement is sent from the receiver by impressing a data message on a subcarrier.

Abstract: A method for providing video programming in a nearly on demand basis is disclosed. A video network includes a video server that operates several video recorders to simultaneously exhibit video performances or programs on a plurality of channels. The video server is controlled in real time in accordance with data presented to it in an exhibition plan. The exhibition plan calls for two or more channels to show the same program on a time offset basis. Due to the offset in exhibiting a given program, a subscriber may view a program at any time, from the beginning of a program, by waiting for a period of time that is no longer than the offset. Preferably, this offset is substantially shorter than the run time of the program. The channels carrying this program are unscrambled prior to the beginning of the program and for a predetermined duration into the program so that subscribers may preview the program. However, the channels are scrambled for the remainder of the exhibition of the program.

Abstract: An asynchronous transmission mode (ATM) memory array capable of storing one ATM packet of data is an n x m array of memory locations, each memory location capable of storing one bit. The array has n columns, where n is the number of bits in an ATM cell of data, and m rows, where m is the number of cells in an ATM packet. The memory array has a plurality of input lines, one for each of said n columns, which together receive n bits simultaneously. It also has n ground lines, one for each of said n columns in said array, each ground line connected to one memory location in each of said n columns in its row; such that each ground line carries the current of only one bit, thereby reducing the noise transients.

Abstract: A secure wireless party line system that can be used by a group of mobile users to communicate with each other like a wired party line but without the cumbersome inconvenience of long wired tether. The party line function is achieved by the use of a fixed wireless repeater. The fixed wireless repeater receives spread spectrum transmissions from all N mobile users at a frequency f1, and passes the received signals through an RF amplifier and upconverter, and then to an IF amplifier and power divider, which converts the received signals down to a convenient intermediate frequency (IF), and feeds N receive spread spectrum processors, each dedicated to receive a coded spread spectrum transmission from one user. The received voice outputs from the N users are then combined in a N-channel voice data multiplexer, and broadcast at a frequency f2 to all users with a common spread spectrum code word added by a transmit spread spectrum processor.

Abstract: An X-geometry optical switch includes primary and secondary input branch waveguides merging at a junction, and first and second output branch waveguides optically coupled to the input branches at the junction. In a dual electrode configuration, one electrode is positioned on the primary input branch waveguide and the other electrode on one of the input branch waveguides. By applying a common or opposite polarity bias to the electrodes, changes in the waveguide refractive optical indices are produced so that light propagating through the primary input is directed to one of the output branch waveguides in accordance with adiabatic modal evolution. In another X-geometry optical switch, the electrode on the output branch is eliminated by fabricating the output branch waveguides to exhibit a natural index asymmetry. Accordingly, since there is a normal ON-OFF path designation without biasing, only the single electrode on the primary input branch waveguide is necessary to effect switching.

Abstract: A tunable optical amplifier is used as a wavelength-selective high-gain element in a subcarrier-multiplexed fiber optic transmission system for providing a direct optical domain-to-baseband conversion of a selected optical channel. A high-speed diode laser optical transmitter is modulated by a plurality of independent information channels that are carried on separate, appropriately spaced carrier frequencies. An optical receiver, coupled to the transmitter by way of an optical fiber, includes a tunable narrow-bandpass semiconductor laser optical amplifier having a gain bandwidth smaller than wavelength distances between adjacent ones of the carrier frequencies, a photodetector coupled to the output of the amplifier, and polarization controlling means coupled to the fiber in front of the optical amplifier for maximizing gain in the optical amplifier.

Abstract: Apparatus is disclosed which is advantageously used in local area, metropolitan-area, and wide-area optical networks having a dual bus architecture, permitting significantly increased distance before termination or regeneration of the optical signal. A portion of the received optical signal is tapped from a fiber, converted to an electrical signal, before presentation to a node. That remaining portion of the received optical signal enters a fiber delay line and is amplified by an optical amplifier. Data to be transmitted from a node is converted from an electrical signal to an optical signal and transmitted on the bus.

Abstract: A host acting as an optical emitter and a process of making the same for the .sup..about. 1.3 .mu.m to .sup..about. 1.55 .mu.m spectral region utilized in optical communications is disclosed. The host is Cr-activated willemite (Zn.sub.2 SiO.sub.4). Efficient band-emission at room temperature, with peak at 1.42 .mu.m, is observed on exiting the material in the near infrared, typically at 730 nm and 829 nm.

Abstract: In a vector transform coding (VTC) scheme for image and video compression, a multi-layered codebook structure and a dynamic bit-allocation scheme in the vector transform domain are employed. The main advantage of this technique is that distortion is controlled by dynamically allocating more bits to vectors causing larger distortions and less bits to vectors causing smaller distortions.

Abstract: In a cellular system configuration, the location of a mobile station is determined from the acquisition of cellular network data pertaining to the mobile station, and the translation of such network data into a corresponding geographical position profile. The cellular system includes a mobile station locator entity for receiving from a mobile switching center the network data such as cell and/or sector ID and trunk group member number. The mobile station locator translates the network data into position information such as geographic coordinates (latitude and longitude), resolution (radius), and angle values for sectorized cells.

Abstract: An asynchronous transfer mode switch with shared memory under the control of a content addressable memory, receives serially through a plurality of input ports a plurality of cells of digital data packets during a specific time period, each packet having a header. The header of each said cell is processed and temporarily stored. The data bits of each cell are temporarily stored, and transferred in parallel to a random access memory, using available addresses in said random access memory. A header processor assigns an arrival number to each received cell, and extracts the output port destination and priority of each cell from said headers. A content addressable memory stores the arrival number, output destination port and priority of each data cell. A read control provides sequentially, in order of priority, arrival numbers, and destination addresses, to said content addressable memory for determining the order in which cells of data are read from said random access memory.

Abstract: A video coding scheme based on wavelet representation performs motion compensation in the wavelet domain rather than spatial domain. This inter-frame wavelet transform coding scheme preferably uses a variable-size multi-resolution motion compensation (MRMC) prediction scheme. The MRMC scheme produces displaced residual wavelets (DRWs). An optimal bit allocation algorithm produces a bit map for each DRW, and each DRW is then adaptively quantized with its respective bit map. Each quantized DRW is then coded into a bit stream.

Abstract: A Y-junction optical switch includes an input branch and two output branches optically coupled to the input branch at a junction. A single one of the output branches has an electrode. The two output branches are designed to have dissimilar optical refractive indices under a non-biasing condition.

Abstract: A cryptography-based entity authentication device (EAD) operated by a remote entity located at a subscriber site enables a telephone switch or computer system to identify and verify the authenticity of the entity. In one embodiment, the EAD encrypts a random digital sequence transmitted by a host facility and returns the encrypted signal to the host for comparison with another encryption signal generated locally by the host. If a match is detected, this serves as confirmation that the remote entity possesses the same encryption key as the host, therefore verifying the authenticity of the remote entity. Otherwise, the entity is deemed fraudulent and access is denied. In another embodiment, the host and subscriber site each include a respective time generation means which are maintained in relative time synchronicity. The EAD generates and encrypts a time signal for comparison with another encrypted time signal generated locally by the host.