Abstract:
An approach is provided for supporting carrier synchronization in a digital broadcast and interactive system. A carrier synchronization module receives one or more signals representing a frame that includes one or more overhead fields (e.g., preamble and optional pilot blocks and one or multiple segments separated by pilot blocks). The module estimates carrier frequency and phase on a segment by segment basis and tracks frequency between segments. Carrier phase of the signal is estimated based upon the overhead field. Estimates carrier phase of random data field are determined based upon the estimated phase values from the overhead fields, and upon both the past and future data signals. Further, the frequency of the signal is estimated based upon the overhead fields and/or the random data field. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.
Abstract:
A digital communications system and method to transmit and receive a digital communications signal wherein the digital signal has a plurality of frames, wherein at least two modulations are supported, and wherein each of the plurality of frames has the same number of symbols.
Abstract:
An approach is provided for supporting carrier synchronization in a digital broadcast and interactive system. A carrier synchronization module receives one or more signals representing a frame that includes one or more overhead fields (e.g., preamble and optional pilot blocks and one or multiple segments separated by pilot blocks). The module estimates carrier frequency and phase on a segment by segment basis and tracks frequency between segments. Carrier phase of the signal is estimated based upon the overhead field. Estimates carrier phase of random data field are determined based upon the estimated phase values from the overhead fields, and upon both the past and future data signals. Further, the frequency of the signal is estimated based upon the overhead fields and/or the random data field. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.
Abstract:
The present invention provides compounds having formula (I), wherein R1, R2, R3 and n are as described generally and in classes and subclasses herein, and additionally provides pharmaceutical compositions thereof, and methods for the use thereof in the treatment of inflammatory or autoimmune and proliferative disorders and as inhibitors of cell adhesion molecule expression and inflammatory cytokine signal transduction generally
Abstract:
A method and apparatus for providing an asymmetrical backwards compatible communications signal that is capable of being decoded by QPSK and OQPSK receivers as well as PSK and QAM receivers is provided. The invention comprises a timing error accumulator coupled to a first bit stream. The first bit stream includes content that is common to the QPSK/OQPSK receiver and to the PSK/QAM receiver. A phase error accumulator is coupled to a second bit stream and adjusts the phase of symbols in the second bit stream. A phase and timing error compensator is coupled to the phase error accumulator and the timing error accumulator and adjusts the first and second bit streams received from the phase error accumulator and the timing error accumulator in order to reduce timing and phase errors. A higher order modulator coupled to the phase- and timing error compensator is also provided. The higher order modulator processes the first and second bit streams to provide the asymmetrical backwards compatible signal.
Abstract:
The present invention provides compounds having formula (I), wherein R1, R2, R3 and n are as described generally and in classes and subclasses herein, and additionally provides pharmaceutical compositions thereof, and methods for the use thereof in the treatment of inflammatory or autoimmune and proliferative disorders and as inhibitors of cell adhesion molecule expression and inflammatory cytokine signal transduction generally.
Abstract:
An approach is provided estimating non-linear characteristics of an amplifier (such as a Travelling Wave Tube Amplifier) used to amplify a composite signal in a radio communication system. The composite signal, which includes a plurality of inbound signals overlay on an outbound signal, is sampled. The outbound signal is utilized as a training signal. Coarse estimates of the response of the amplifier is generated based on the samples of the composite signal and the training signal. Further, the interference associated with the inbound signals are removed from the estimation of the response of the amplifier by curve-fitting and estimating interference characteristics of the composite signal. An estimated response of the amplifier is thus output, and can be utilized to provide accurate non-linearity compensation and cancellation.
Abstract:
An approach for identifying a particular carrier among a plurality of carriers in a satellite communication system is disclosed. A transmitter multiplies an encoded signal by a prescribed periodic sequence to form a watermarked signal and transmits the watermarked signal associated with a particular carrier over a communication channel. A receiver tunes to one of the carriers and extracts a data sequence from the one carrier. The receiver multiplies the data sequence with the prescribed periodic sequence to form another watermarked signal and determines whether the watermarked signals match.
Abstract:
A regulation circuit for a current-fed power converter having a power switch adapted to transfer power to a transformer. In one embodiment, the regulation circuit includes a switching network coupled to a tapped winding of the transformer and operable to vary a turns ratio of the transformer thereby regulating an output voltage of the power converter.
Abstract:
For use with a flyback converter having a modulator for providing a main switch control signal thereto and main and cross-regulated output circuits, the cross-regulated output circuit subject to ringing and resulting voltage excursion, a voltage excursion controller and a method of operating the same. In one embodiment, the controller includes: (1) a delay circuit, coupled to the modulator, that generates a delay signal based on the main switch control signal and (2) an auxiliary switch, associated with the cross-regulated output circuit, that receives the delay signal and opens to isolate at least a portion of the ringing within said cross-regulated output circuit.