摘要:
A satellite receiver includes a down converter for providing a received signal and a demodulator having at least two demodulation modes for demodulating the received signal, wherein one demodulation mode is hierarchical demodulation and another demodulation mode is layered demodulation.
摘要:
The power of the respective codes used by the first and second error detection/correction circuitry are such that the coded bit error rate of the first data stream is more closely matched to the coded bit error rate of the second data stream. A hierarchical QAM system allows the transmission of different sources by embedding the relative constellation points. The hierarchical QAM transmitter encodes the first data stream using a code having a first detection/correction power and encodes the second data stream using a code having a second detection/correction power.
摘要:
A method and apparatus for staggercasting a plurality of content representative signals includes encoding a first and a corresponding second signal representing each of the plurality of content representative signals. A composite signal is generated comprising the plurality of first and second encoded signals. In the composite signal, each respective second encoded signal is delayed with respect to the corresponding first encoded signal. The first and second encoded signal representing a selected one of the content representative signals is extracted to reproduce the selected content representative signal. The extracted first encoded signal is decoded if an error is detected in the extracted second encoded signal, otherwise the extracted second encoded signal is decoded. When a different content representative signal is newly selected, the first extracted encoded signal is decoded until the delayed second extracted encoded signal is available.
摘要:
A method and apparatus for staggercasting, encodes a first signal representing content and encodes a second signal representing the content using encoding relatively more robust than the encoding of the first encoded content representative signal. A composite signal including at least the first and second encoded signals is generated, in which one of the first and second encoded signals is delayed with respect to the other encoded signal. If an error is detected in the composite signal, then the undelayed encoded signal is decoded to reproduce the content. Otherwise, the delayed encoded signal is decoded to reproduce the content.
摘要:
A method for creating a secure sub-network on a public network that includes a set of devices. The secure sub-network is to include a subset of devices from among the set of devices. An access card is provided having a first private key comprised thereon. The access card is scanned to determine the first private key, by the subset of devices. A master device is determined from among the subset of devices. A second private key is selected and a public key is computed based on the second private key, by the master device. The second private key is only known to the master device. The public key is sent to the set of devices, by the master device. A shared encryption key is computed, and an encryption is requested of any subsequent messages between any of the devices comprising the subset of devices using the shared encryption key.
摘要:
A Video-on-Demand Server architecture transmits a plurality of pre-coded programs having different bit rates across a fixed bandwidth channel. For each program, a generator generates a plurality of different bit rate representations for each program. Each generator also provides control information at each of a plurality of successive time windows T for each bit rate representation. The control information provides a bit rate and a quality measure during each time window T. The control information enables a statistical multiplexer to select a bit rate representation for each program during each time window T to maximize the quality of the selected representations while not exceeding the total available channel capacity.
摘要:
A system, apparatus and/or method provides frequency response adjustment of an RF input filter of an RF tuner based on impedance of an antenna system that is providing reception of RF signals to the RF tuner. The frequency response adjustment is preferably accomplished dynamically and/or with respect to each frequency tuned. Particularly, the system, method and/or apparatus provides compensation at the RF tuner level for mistuning effects produced on the RF tuner by antenna system impedance presented at the antenna input that is other than a designed for impedance. Frequency response of an RF input filter for the RF tuner is electronically adjustable with an independent or semi-independent control voltage signal based on one or more measured parameters of a tuning frequency. Frequency response adjustment may include adjustment of a center frequency of the RF input filter bandpass frequency range and/or altering the bandpass frequency range of the RF input filter. The subject invention expands the capability of an RF signal receiver, particularly one using at least one electronically adjustable RF filter at the input of an electronic alignment type tuner.
摘要:
In a digital broadcast communications system, a higher priority component and a lower priority component are broadcast from a transmitter to a receiver. Each of these components generates a main and a supplemental signal, and each supplemental signal is advanced in time with respect to the corresponding main signal. The main and supplemental signals for both the higher and lower priority components are combined into a single signal, which is broadcast to a receiver. In the receiver, the time advanced supplemental signals are stored in a buffer to time align them with their corresponding main signals. Both main signals are processed in the normal manner in the receiver, and are also monitored to detect a fading event. When a fading event is detected, the corresponding buffered supplemental signals are substituted for the faded main signals and normal processing continues.
摘要:
Synchronization of a powerline modem network (10) with a plurality of devices is provided. A plurality of devices (16 and 18) each include a powerline modem (20) and a clock circuit (22) for synchronizing a data rate. The powerline modem permits data transmission between the plurality of devices over a powerline network on data carriers (28). A synchronization signal is transmitted over the powerline network. The synchronization signal includes a carrier (30) operating at a frequency different from the data carriers. The synchronization signal provides each of the plurality of devices a time reference to synchronize the data rate.
摘要:
A wireless telephone system, having one or more wireless handsets and a base unit. Each handset has a handset transceiver, and the base unit has a base transceiver and a handset docking station, which has a wired interface. The base unit digitally communicates over an RF channel with a handset via its handset transceiver only if the handset has previously been initialized by the base unit. The handset is initialized via the wired interface when it is physically docked in the docking station.