Abstract: In a communications network comprising a plurality of interconnected nodes, each node comprises at least one network device requiring allocated transmission channels, a switch connected to the network device for configuring transmission channels connected to other nodes, and a configuration controller connected to the network device and to the switch for controlling configuration of the transmission channels. The configuration controller receives signals from the network device indicative of traffic load on the network device, processes the received signals to determine that reconfiguration of the transmission channels is favoured and determines a favoured reconfiguration of the transmission channels.

Abstract: A broadcast methodology for activation of virtual circuits in a large scale data network at a controlled rate is disclosed. The method includes, at a node within the network, alternate steps of broadcasting activation signals for a predetermined number of the of virtual circuits and delaying a time interval. The alternate steps are repeated until all the activation signals have been broadcast.

Abstract: One or more streams from a number of real-time video streams available to be transmitted across a communications network, are selected for display on respective terminals of a first, and at least one other user. First, a policy of the first user for making the selection, is determined, the policy containing conditions to be evaluated, selectable by the first user. Then, which streams to select for the first user is determined dynamically by evaluating the current conditions according to the first user's policy. Only the selected streams are passed for display on the terminal of the first user, independently of selections made for passing to the other users. Dynamic selection from multiple streams enables the user to concentrate on the content not the form of presentation. Individual control of what is displayed, independent of what other users see, enables tailoring to video conferences to be handled more easily.

Abstract: In a Data Access Transport Service (DATS), Data Service Providers (DSPs) share dial-in access (e.g. analog modem or Integrated Services Digital Network (ISDN) access) resources from a common pool maintained by a Local Exchange Carrier (LEC) (or potentially a DSP. A system is disclosed wherein a Network Controller (NC) performs the role of DSP service partitioning, quota enforcement, and resource load balancing to ensure that a DATS provider can provide a high quality of service (availability, response time & consistent bandwidth) to subscribed DSPs and their end-users. The Network Controller assists in Internet Data call establishment and tear-down, with the ability to refuse calls when the associated DSP has exceeded its service quota. The Network Controller also assists in the routing of calls to one of the DSPs Network Gateways (or data routers), using a load balancing scheme that maintains a pre-defined relative load on given DSP Network Gateways.

Abstract: In methods and apparatus for suppressing echo of a far end signal encoded using LPC-based compression in a near end signal encoded using LPC-based compression, parameters of each frame of the near end encoded signal are processed without synthesizing a speech signal from the near end encoded signal to determine whether sufficient echo to merit echo suppression is present in the frame. Upon determining that insufficient echo to merit echo suppression is present in the frame, the parameters of the frame are passed unmodified. Upon determining that sufficient echo to merit echo suppression is present in said frame, the parameters of the frame are modified without synthesizing a speech signal to suppress echo in the frame. The methods and apparatus are particularly suitable in codec bypass applications.

Abstract: In methods and apparatus for computing measures of echo of a far end signal in a near end signal, the evolution over time of frequency spectra of the near end and far end signals are compared to compute a measure of the echo. A far end spectrum of the far end signal and a near end spectrum of the near end signal are determined for each of a plurality of successive time intervals. A respective measure of correlation is determined for each of a plurality of spectrum pairs, each spectrum pair comprising a respective near end spectrum and a respective far end spectrum, the far end spectrum corresponding to a time interval which lags a time interval corresponding to the near end spectrum by a respective time lag. The measures of correlation are compared to determine a maximum measure of correlation which can be used as a measure of echo. The echo measure computation technique is particularly suitable for use in echo suppressors for digital cellular telephony systems, but has other applications.

Abstract: In methods and apparatus for generating an LPC-encoded noise signal from an LPC-encoded speech signal, excitation parameters of the LPC-encoded speech signal for a current frame are randomized upon detection of speech in the current frame. For frames in which no speech is detected, LPC coefficients and frame energy for the current frame may be replaced with respective averages calculated over the current frame and a plurality of preceding frames. For frames in which speech is detected, LPC coefficients for the current frame may be replaced with respective averages of LPC coefficients used to replace LPC coefficients of an immediately previous frame. The comfort noise generation technique is particularly suitable for use in echo suppressors for digital cellular radio systems.

Abstract: In methods and apparatus for distinguishing stationary signals from non-stationary signals, a set of Linear Predictive Coding (LPC) coefficients characterizing spectral properties of the signal for each of a plurality of successive time intervals, including a current time interval, is determined. The LPC coefficients are averaged over a plurality of successive time intervals preceding the current time interval, and a cross-correlation of the LPC coefficients for the current time interval with the averaged LPC coefficients is determined. The signal is declared to be stationary in the current time interval when the cross-correlation exceeds a threshold value, and is declared to be non-stationary in the current time interval when the cross-correlation is less than the threshold value. The methods and apparatus are particularly applicable to detection of transitions between an absence of speech state, characterized by a stationary signal, and a presence-of-speech state characterized by a non-stationary signal.

Abstract: A topology verification process for controlling a Personal Communication Services (PCS) system which includes a plurality of Cordless Fixed Parts (CFP)s. The process includes mapping the spatial relationships of the CFPs utilizing Received Signal Strength Indication (RSSI) vectors resulting from test signals transmitted between the CFPs, to establish the topology of the system; repeating the mapping process after any disruption of power to the system, and comparing the results. Any significant change in the results, would be highly indicative of a potential change in the geographic area of operation of the system, and can be used to initiate disablement of the system operation.

Abstract: In methods and apparatus for at least partially automating a telephone directory assistance function, directory assistance callers are prompted to speak locality or called entity names associated with desired directory listings. A speech recognition algorithm is applied to speech signals received in response to prompting to determine spoken locality or called entity names. Desired telephone numbers are released to callers, and released telephone numbers are used to confirm or correct at least some of the recognized locality or called entity names. Speech signal representations labelled with the confirmed or corrected names are used as labelled speech tokens to refine prior training of the speech recognition algorithm. The training refinement automatically adjusts for deficiencies in prior training of the speech recognition algorithm and to long term changes in the speech patterns of directory assistance callers served by a particular directory assistance installation.

Abstract: In methods and apparatus for processing a speech signals comprising a plurality of successive signal intervals, each signal interval containing no speech sounds is classified as a noise interval, and LPC coefficients are calculated for each noise interval based on the samples of that noise interval and on the samples of a plurality of preceding signal intervals. When noise intervals encoded using LPC coefficients calculated as described above are reconstructed, the subjectively annoying "swishing" or "waterfall" effects encountered in conventional LPC speech processing systems are reduced or eliminated.

Abstract: In methods and assemblies for packaging opto-electronic devices and for coupling optical fibers to the packaged devices, a housing has a cavity for receiving an opto-electronic device and an opening into the cavity. A window is placed across the opening to seal the opto-electronic device in the cavity. The window comprises a plurality of substantially parallel optical fiber sections joined side-by-side. An alignment and retention arrangement is mechanically coupled to the housing and is operable to align an optical fiber to the opto-electronic device through the window and to retain the optical fiber in that alignment. The methods and assemblies are particularly applicable to cost reduced packaging of opto-electronic devices for communications applications.

Abstract: In methods and apparatus for providing suppressed ringing access to a subscriber line, a connection request is sent from a server to a telecommunications switch and the switch performs a connection routine in response to the connection request to connect the server to the subscriber line. The connection routine is adapted to avoid audible ringing of a telephone set connected to the subscriber line. The connection request comprises a signal indicating a subscriber line to which the server is to be connected and a signal indicating that suppressed ringing access to that subscriber line is desired. The methods and apparatus avoid the need for especially provisioned trunks between the server and the terminating switches by including in the connection request a signal indicating that suppressed ringing is desired and by making the telecommunications switch responsive to that signal.

Abstract: In methods and apparatus for monitoring the performance of optical transmission systems, an optical signal is modulated with a low frequency dither signal to provide a modulated optical signal having a known modulation depth. A portion of the optical signal is tapped, and both a total power and a dither amplitude of the tapped portion of the optical signal are measured. Both signal and noise components of the tapped portion of the optical signal are estimated by comparing the measured dither amplitude to the measured total signal power. In wavelength division multiplexed optical transmission systems, optical signals at each distinct wavelength are modulated with distinct dither signals and dither amplitudes of each distinct dither signal detectable in the tapped portion of the optical signal are measured. Both signal and noise components are estimated for the optical signals at each distinct wavelength.

Abstract: In methods and apparatus for estimating carrier-to-interference ratios of signals transmitted between cellular radio base stations and mobile units, a SAT signal is transmitted from a base station to a mobile unit served by that base station. The mobile unit receives the SAT signal and retransmits the received SAT signal to the base station. A first order autoregressive parameter is calculated for the received SAT signal at the base station is correlated with a tabulated carrier-to-interference ratio estimate to estimate the carrier-to-interference ratio of the signals.

Abstract: In methods and apparatus for at least partially automating a telephone directory assistance function, directory assistance callers are prompted to speak locality or called entity names associated with desired directory listings. A speech recognition algorithm is applied to speech signals received in response to prompting to determine spoken locality or called entity names. Desired telephone numbers are released to callers, and released telephone numbers are used to confirm or correct at least some of the recognized locality or called entity names. Speech signal representations labelled with the confirmed or corrected names are used as labelled speech tokens to refine prior training of the speech recognition algorithm. The training refinement automatically adjusts for deficiencies in prior training of the speech recognition algorithm and to long term changes in the speech patterns of directory assistance callers served by a particular directory assistance installation.

Abstract: An N=3 frequency plan for 60 degree sector transmit sector receive (STSR) cell sites is based upon dividing available channels into 18 frequency groups. Frequency assignment is in accordance with an odd-even cyclic distribution of channels which provides a three-channel separation between sectors within a cell and at least seven-channel separation between adjacent cells. This ensures adequate channel isolation between sectors and improved adjacent channel C/I performance throughout the network. The N=3 frequency plan increases channel capacity by approximately 38% in AMPS and 114% in TDMA-3.

Abstract: In novel sampling methods and apparatus, a repetitive waveform is sampled at a sampling phase which alternates at a phase alternation frequency between a fixed reference phase and a variable phase while changing the variable phase progressively and periodically. The amplitude of a component of the resulting signal at the phase alternation frequency is detected to derive a lower frequency analog of the sampled waveform. The sampling methods and apparatus are particularly useful for electro-optic sampling of very high frequency waveforms in semiconductor devices.

Abstract: In methods and apparatus for controlling a phase relationship of two signals, a supplementary phase adjustment signal is generated. The supplementary phase adjustment signal has a zero value when an actual phase relationship of the two signals deviates from a desired phase relationship by less than a threshold phase deviation, and has a non-zero value when the actual phase relationship deviates from the desired phase relationship by more than the threshold phase deviation. The phase relationship of the two signals is adjusted in response to a sum of the supplementary phase adjustment signal and a phase adjustment signal which is proportional to the deviation of the actual phase relationship from the desired phase relationship. The methods and apparatus are particularly applicable to alignment of clock signals with data signals.

Abstract: In methods and apparatus for non-contact testing of an electronic circuit board at least one electromagnetic emission sensing probe is disposed a short distance from a circuit board under test, the circuit board is operated while sensing electromagnetic emission from a region of the circuit board near the probe, and a time domain representation of the sensed electromagnetic emission is developed. The time domain representation of the sensed electromagnetic emission is compared to a time domain representation of electromagnetic emission of a circuit board known to be operating properly. Preferably, an array of electric field sensing probes is used to sense emissions from several regions of the circuit board simultaneously, and time domain representations of the sensed electromagnetic emissions are simultaneously developed and compared to respective time domain representations of electromagnetic emissions from circuit boards known to be operating properly.