Abstract: Methods and apparatus are described for management of traffic comprising a statistical shaper having a plurality of inputs each for receiving a data stream and a plurality of outputs forming a variable rate bit streams; a multiplexer which combines the bit streams to form an output stream; a modulation stage which is operable to use one or more of a plurality of different modulation schemes to modulate the bit streams onto an output bearer; and, a controller which is operable to control the amount of data arriving at the modulation stage. The controller performs rate control of the data arriving at the modulation stage so that the rate of data output in the output stream from the modulator stage is within a predetermined limit for the transmission channel. For example if the modulation rate for any one bitstream changes, this would alter the rate of data transmission after the modulation stage except that excess data is stored in buffers.

Abstract: Methods and apparatus are described for management of traffic comprising a statistical shaper having a plurality of inputs each for receiving a data stream and a plurality of outputs forming a variable rate bit streams; a multiplexer which combines the bit streams to form an output stream; a modulation stage which is operable to use one or more of a plurality of different modulation schemes to modulate the bit streams onto an output bearer; and, a controller which is operable to control the amount of data arriving at the modulation stage. The controller performs rate control of the data arriving at the modulation stage so that the rate of data output in the output stream from the modulator stage is within a predetermined limit for the transmission channel. For example if the modulation rate for any one bitstream changes, this would alter the rate of data transmission after the modulation stage except that excess data is stored in buffers.

Abstract: An elementary two-stream transport multiplexer provides for the addition of services contained in a transport stream to a pre-existing transport stream. The elementary multiplexer includes a pair of transport demultiplexers, a processor and a transport remultiplexer. The demultiplexers demultiplex a pair of input transport streams to their constituent service components and service control information tables. The service control information tables are routed to the processor which combines and reconfigures the information within the tables to provide a single set of output service control information tables. The demultiplexers filter the service components based on the output service control tables. The transport remultiplexer multiplexes the output tables with the filtered streams to provide an output transport stream.

Abstract: A system and method are disclosed for digitally representing reference and data signals transmitted in the vertical blanking interval (VBI) of an analog television waveform such as NTSC or PAL. The system includes means for compressing the digital representation of the VBI signals. A broad range of reference and data signals is capable of being represented. The compressed representations of the VBI signals are particularly suitable for inclusion in an MPEG2 compliant signal carrying compressed digital video and audio.

Abstract: A fractionally-spaced adaptively-equalized self-recovering digital receiver includes a fractionally-spaced adaptive filter for equalizing channel distortion which includes means for adaptively adjusting the coefficients of the fractionally-spaced filter with a self-recovering (blind) algorithm or a decision directed algorithm; means for changing the timing at which the data is sampled; means for estimating the sampling frequency offset in order to derive the optimal timing; means for synchronizing the signal resampling at the symbol rate using the statistics of the received data samples; means for evaluating the profile of the equalizer coefficients; and means for tracking carrier frequency offset.

Abstract: A method of carrier tracking in a digital receiver includes adjusting the phase of an equalized signal by a phase correction to compensate for a carrier frequency offset. For a small carrier frequency offset the phase correction is based on a first estimate of phase error and phase velocity of the equalized signal. For a large carrier frequency offset the first phase velocity estimate is controlled by a second phase velocity estimate based on rotation of the data constellation.

Abstract: A fractionally-spaced adaptively-equalized self-recovering digital receiver includes a fractionally-spaced adaptive filter for equalizing channel distortion which includes means for adaptively adjusting the coefficients of the fractionally-spaced filter with a self-recovering (blind) algorithm or a decision directed algorithm; means for changing the timing at which the data is sampled; means for estimating the sampling frequency offset in order to derive the optimal timing; means for synchronizing the signal resampling at the symbol rate using the statistics of the received data samples; means for evaluating the profile of the equalizer coefficients; and means for tracking carrier frequency offset.