摘要:
A store-and-forward architecture which stores and distributes information programs to subscribers on demand includes: information warehouses which archive information programs from multiple service vendors and dispense information programs in segments to central offices in high speed bursts; central offices which manages subscriber's request for service and buffers segments of information programs for delivery to subscribers in real-time under the subscriber's interactive control; and customer premises equipment where a subscriber's requests and control signals for interactive play-out of information program are generated and information programs are received for the subscriber's use.
摘要:
A store-and-forward architecture which stores and distributes information programs to subscribers includes: information warehouses which archive information programs and dispense information programs in segments to central offices in bursts; central offices which manage subscriber's requests for service and buffer segments of information programs for delivery to subscribers in real-time under the subscriber's interactive control; and customer premises equipment. The central offices employ CO buffers, and each CO buffer includes: processors, for administering internal buffer operations and processing subscribers requests based upon the service presentation script and a program presentation map; interfaces for providing external access; busses for internal transport; buffer storage for storing segments of information programs; and memory storage for storing the script and map.
摘要:
In a multipoint data communication system using quadrature-amplitude modulation, a master modem (20) and a plurality of tributary modems (11a, 11b . . . 11n) are interconnected via respective transmission channels (13a, 13b . . . 13n, 16). Adaptive equalizer circuitry (55, 56) in the master modem equalizes the channel from a particular tributary by multiplying samples of signals received from the tributary by an ensemble of tap coefficients associated with the tributary. The tap coefficient ensembles for each tributary are stored in a memory (91) from which they are retrieved at the start of transmission from that tributary. Timing-acquisition circuitry (29) within the master modem adjusts the phase of the latter's sampling circuitry (23, 27) at the start of transmission from a given tributary so that the received signals are sampled at the correct time points. In particular, a timing acquisition signal having spectral components only within the non-rolloff region of the equalized baseband-equivalent transfer function is transmitted by the tributary. The master samples and equalizes the received timing acquisition signal to form a succession of timing acquisiton equalizer outputs. The time by which the operation of the sampling circuitry is to be advanced or retarded is determined as a trigonometric function of two successive ones of the timing acquisition equalizer outputs. The timing acquisition signal is illustratively a double-dotting pattern having a four-symbol-interval period. That period is integrally related to the carrier frequency. This allows the samples needed in order to begin forming the timing acquisition equalizer outputs to be generated by replicating the samples taken over only four symbol intervals.
摘要:
Public wireless communications will increasingly extend into wireless LAN (WLAN) environments in order to meet the ubiquitous access, high data rate, and local services demands of future Internet appliances. By relying on IP-level services mechanisms, the Public Access Mobility LAN (PAMLAN) can simultaneously support different air interfaces, franchises for multiple services providers, and a multi-segment LAN environment including handoffs. The PAMLAN supports virtual operator LANs representing different network services providers, authorization and accounting mechanism, support of multiple air interfaces, and local IP mobility. A router associated with each base station realizes this highly distributed IP networking environment, and a QoS-enabled switched Ethernet core supports virtual networks and QoS services.
摘要:
A data bypass system diverts data calls to a central office based modem bank and a data network at the subscriber's discretion. The data call diversion is based on a data service prefix in the user's dialing string. The data bypass device translates a subsequent telephone address of a data service supplier into a data network address. The data bypass system is either analog or digital and has a line card with a switch that selectively connects the subscriber line to the voice switch or to a data switch or router through two respective concentrators. The line card includes a data call prefix detector that controls the switch in response to a data call prefix that precedes a data call telephone number. The analog bypass system diverts a data call to a modem and a data network before the data call reaches a voiceband filter and an A/D converter of the line card, while the digital bypass system diverts the data call through a wideband filter and an A/D conversion before applying the data call to a modem accepting a digitized line signal. The digital bypass system utilizes a line card with two filter and A/D converter modules, one for voice calls and another for data calls. Instead of being in each line card, all the line cards share a telephone number and data service prefix detector located following the voice call concentrator.
摘要:
An adaptive equalizer and echo canceller jointly respond to a common error difference between the actual output and the quantized digital output of a data receiver in a two-wire digital data transmission system to achieve simultaneous full-bandwith full-duplex operation. Two-wire transmission channels are typically terminated in hybrid balancing networks which because of their fixed impedances permit "echoes" of the transmitted signal to interfere with reception of the much weaker incoming signal. Both the equalizer and canceller are adaptively adjustable transversal structures.
摘要:
One aspect of the present invention is a method for the wireless transmission of information from one or more antennas to one or more separate users. The method comprises processing information to produce transmission vectors that minimize simultaneous interference between separate user channels and adjusting the radiation patterns to minimize total system radiation power for users specified capacities. In another aspect, the present invention includes apparatus and methods for providing multiple users of a network with information in such a manner that only the user that the signals are intended for receives the information.
摘要:
A speaker verification and voice command system utilizing speech templates stored in an integrated circuit card is disclosed. To verify the user's identity, a comparison is made between a plurality of reference speech templates stored in the user's integrated circuit card and a test template formed from a word or words spoken by the user.
摘要:
A system is described for digital, as opposed to the usual analog, recording of a sound track in synchronism with a visual image on a motion picture film and automatically reproducing the sound in synchronism with the visual image. In one embodiment of the invention, a camera employs a linear array of light-emitting diodes across the sound track to enter a digital representation of the sound on the same frame as the synchronous visual image. The digital, specifically binary, signals which excite the light-emitting diodes are produced by analog to digital conversion of samples of the sound waveform. The binary representations are entered into shift registers at a uniform rate, and read out to the light-emitting diodes in a burst during the film advance interval immediately following shutter closure, thereby entering on the film track an optical record of all the binary pulses derived from sound produced during the just concluded frame interval. A projector capable of presenting the film sound and visual image in synchronism employs a strip of photodetectors to detect the binary pulses and a digital to analog converter to recover the original sound. Other embodiments of the invention utilize a fiber optics array, an image tube with fiber optic faceplate, or a laser scanner to enter the binary pulses on the optical sound track.
摘要:
One aspect of the present invention is a method for the wireless transmission of information from one or more antennas to one or more separate users. The method comprises processing information to produce transmission vectors that minimize simultaneous interference between separate user channels and adjusting the radiation patterns to minimize total system radiation power for users specified capacities. In another aspect, the present invention includes apparatus and methods for providing multiple users of a network with information in such a manner that only the user that the signals are intended for receives the information.