Abstract: A method of optical communication includes generating an amplified optical signal from at least a portion of a first optical signal having a first carrier wavelength, ?1. The amplified optical signal is applied to Brillouin media to stimulate generation of a Brillouin effect signal at a wavelength ?2. The Brillouin effect signal is modulated to produce a second optical signal having a second carrier wavelength, ?2. In one embodiment, the first optical signal is a downstream optical signal and the second optical signal is an upstream optical signal of a passive optical network.

Abstract: An apparatus for generating environmental element predictions at a point location includes a receiver for collecting broadcast environmental element prediction data. A processor generates at least one environmental element prediction for the point location.

Abstract: A method of calibrating longitudinal balance for a subscriber line interface circuit includes providing a first and a second driver of a differential driver pair for driving a subscriber line. An output of each of the first and second drivers is coupled to a common output. The common output is coupled to an input of the first driver. The gain of at least one of the first and second drivers is adjusted until a calibration signal (V1) present at the input of the first driver is substantially the same as a calibration signal (V2) present at the input of the second driver.

Abstract: Recovery systems and methods for sustaining the operation of a plurality of networked computers (20a,20b) in the event of a fault conditions are described. The basic recovery system comprises a plurality of virtual machines (31a,31b) installed on a recovery computer (30), each virtual machine being arranged to emulate a corresponding networked computer, and the recovery computer being arranged, in the event of a detected failure of one of the networked computers, to activate and use the virtual machine which corresponds to the failed networked computer (20). The recovery computer (30) may be located on the same network (12) as the networked computers (20), or alternatively on a remotely located local network in case of failure of the entire local network (12).

Abstract: A method of providing dispersion compensation includes providing a dispersion signal indicative of an amount of dispersion for at least one channel of a multi-channel optical signal. A dispersion compensator is controlled in accordance with the dispersion signal to optically compensate for the dispersion of the optical signal.

Abstract: A method of optical communication includes providing a plurality of optical signals each associated with a distinct channel of a composite optical signal. A unique pilot tone signature is superimposed on each channel. The spectral composition of each signature includes a plurality of frequencies. In one embodiment, binary frequency shift keying at a frequency fm is used to shift between instantaneous frequencies f1 and f2 wherein f2+?f=f1??f=fc. Choosing ? ? ? f f m ? 1.1602 produces a spectrum having a plurality of dominant components at least some of which have substantially the same amplitude. A method of detecting the presence of a selected pilot tone signature having a plurality n of dominant spectral components F1 . . . Fn includes generating a power spectrum P0(f). Sk(f) is calculated as a product of a plurality of frequency shifted versions of P0(f), where k?{1 . . . n}. The existence of a dominant spectral component at Fk indicates the presence of the selected pilot tone signature.

Abstract: A variable power supply is controlled to supply power at approximately a first supply level for an electronic device. The variable power supply is controlled to control a transition of the power from approximately the first supply level toward a second supply level prior to controlling the variable power supply to supply power at approximately the second supply level for the electronic device. One or more power supply controller parameters are dynamically controlled.

Abstract: One embodiment of an apparatus for switching a transistor includes a first current mirror providing iB=K1i1, as a transistor base current, wherein the first current mirror is selectively driven by a current source i B ? ? MAX K 1 . A second current mirror providing a feedback signal i2=K2iD to the first current mirror such that i 1 + i 2 = i B ? ? MAX K 1 , wherein iD contributes to the transistor collector current, wherein iB=iBMAX?K1K2iD.

Abstract: A subscriber line interface circuit apparatus includes tip/ring sense circuitry generating a tip sense signal and a ring sense signal from three sensed currents, wherein the tip sense signal and the ring sense signal correspond to subscriber loop tip and ring currents, respectively. In one embodiment, the tip/ring sense circuitry includes a current mirror generating first and second mirrored sense currents from a first sense current proportional to a battery feed node voltage of a subscriber loop. Current differencing circuitry provides the tip sense signal from a difference between the first mirrored sense current and a second sense current associated with a tip line of the subscriber loop. The current differencing circuitry provides the ring sense signal from a difference between the second mirrored sense current and a third sense current associated with a ring line of the subscriber loop.

Abstract: An apparatus includes a rotor, a stator, and a plurality of magnets forming bearing poles coupled to a selected one of the stator or the rotor. The apparatus further includes a plurality of shorted coils coupled to the other of the stator and the rotor. The plurality of bearing poles and shorted coils co-operate to form an electrodynamic bearing during rotation of the rotor. The electrodynamic bearing supports the rotor either axially or radially during operation. Hydrodynamic bearing surfaces are provided for generating a hydrodynamic bearing between the rotor and stator. The plurality of magnets may comprise a plurality of distinct magnetic elements or a single element comprising a plurality of distinct magnetic domains. The plurality of distinct magnetic elements or domains may be arranged to form a Halbach array.

Abstract: A multiprocessing apparatus includes a memory and a plurality (M) of processors coupled to share the memory. Access to the memory is time-division multiplexed among the plurality of processors. In one embodiment, a selected processor retrieves M words of instruction forming K instructions during a given clock cycle. The selected processor executes M?K NOP instructions if K<M.

Abstract: Methods and apparatus for coupling outgoing analog audio signals to a subscriber line are described. One method includes the step of receiving the outgoing audio signal. The outgoing audio signal is coupled to the subscriber line through a plurality of transistors coupled in a common base configuration. In one embodiment, linefeed driver control signals for controlling battery feed to the subscriber line are received on the same signal lines as the outgoing audio signal. A subscriber line interface circuit apparatus includes a first circuit for coupling a received outgoing audio signal to a subscriber line. The first circuit couples the received outgoing audio signal to the subscriber line through a common base isolation stage. In various embodiments, the common base isolation stage comprises a plurality of bipolar junction transistors coupled in a common base configuration or a plurality of field effect transistors coupled in a common gate configuration.

Abstract: A method includes the step of providing subscriber loop pull-down circuitry operating in a first voltage domain. The subscriber loop pull-down circuitry decreases at least one of a tip and a ring line current in response to a corresponding pull-down control signal. The method further includes the step of providing control circuitry operating in a second voltage domain, wherein the first and second voltage domains are substantially distinct. The control circuitry varies the pull-down control signal to decrease a selected one of the tip and ring line currents in response to a sensed current corresponding to an associated one of a tip pull-down current and a ring pull-down current. A subscriber line interface circuit apparatus includes pull-down circuitry operating in a first voltage domain. The pull-down circuitry varies line currents of the tip and ring lines in response to a pull-down control signal provided by control circuitry operating in a second voltage domain.

Abstract: A method of optical communication includes providing a plurality of optical signals each associated with a distinct channel of a composite optical signal. A unique pilot tone signature is superimposed on each channel. The spectral composition of each signature includes a plurality of frequencies. In one embodiment, binary frequency shift keying at a frequency fm is used to shift between instantaneous frequencies f1 and f2 wherein f2+?f=f1??f=fc. Choosing ? ? ? f f m ? 1.1602 produces a spectrum having a plurality of dominant components at least some of which have substantially the same amplitude. A method of detecting the presence of a selected pilot tone signature having a plurality n of dominant spectral components F1 . . . Fn includes generating a power spectrum P0(f). Sk(f) is calculated as a product of a plurality of frequency shifted versions of P0(f), where k?{1 . . . n}. The existence of a dominant spectral component at Fk indicates the presence of the selected pilot tone signature.

Abstract: A method of providing dispersion compensation includes providing a dispersion signal indicative of an amount of dispersion for at least one channel of a multi-channel optical signal. A dispersion compensator is controlled in accordance with the dispersion signal to optically compensate for the dispersion of the optical signal.

Abstract: A subscriber line interface circuit apparatus includes a first driver for driving a downstream data signal in a non-voiceband range and a metering signal onto a subscriber line. The apparatus includes a second driver for driving a downstream voice signal in a voiceband range onto the subscriber line. Receiver circuitry is coupled to provide an upstream data signal and an upstream voice signal from an upstream signal carried by the subscriber line. The first driver and receiver circuitry reside on a same first integrated circuit die.

Abstract: A hybrid with a plurality of selectable hybrid input paths each having an associated hybrid input path filter is provided. The hybrid includes a plurality of selectable receive paths each having an associated receive path filter. The hybrid further includes a hybrid output. The selection of any filter is non-mutually exclusive to the concurrent selection of another filter.

Abstract: Methods and apparatus for managing an optical network using pilot tones are provided. One method includes selecting an optical path having a plurality of nodes from a database defining an expected optical network. A detected list of pilot tones associated with each node of the selected optical path is generated. An expected list of pilot tones associated with each node of the selected optical path is generated. The detected and expected lists are compared to identify any mismatched nodes.

Abstract: A subscriber line interface circuit apparatus includes a first driver for driving a downstream data signal in a non-voiceband range onto a subscriber line and a second driver for driving a downstream voice signal in a voiceband range onto the subscriber line. The apparatus includes receiver circuitry coupled to provide an upstream data signal and an upstream voice signal from an upstream signal carried by the subscriber line. The first driver and receiver circuitry reside on a same first integrated circuit die.

Abstract: A subscriber line transceiver apparatus includes an integrated circuit coupling at least one of an upstream and a downstream voice path for carrying voice signals to a subscriber line. The integrated circuit couples at least one of an upstream and a downstream data path for carrying data signals to the subscriber line. The voice signals are communicated within a first frequency range and the data signals are communicated within a second frequency range. The first and second frequency ranges are distinct.