摘要:
A network gateway is configured to facilitate on line and off line bi-directional communication between a number of near end data and telephony devices with far end data termination devices via a hybrid fiber coaxial network and a cable modem termination system. The described network gateway combines a QAM receiver, a transmitter, a DOCSIS MAC, a CPU, a voice and audio processor, a voice synchronizer, an Ethernet MAC, and a USB controller to provide high performance and robust operation.
摘要:
A communication system for coupling telephony or other signals to a broadband network such as a CATV network. The system transmits a multiplex of telephony signals in the forward band of the broadband network, with individual signals directed to an addressed subscriber. Telephony signals returning from subscribers upstream to a headend unit (HIU) are modulated onto the reverse band of the broadband network in a frequency division multiple access (FDMA) arrangement. The upstream modulated telephony signals are received at a telephony network interface at the HIU coupled to the broadband network. A group of reverse band modulated telephony signals are received at a group receiver or channelizer. The group receiver processes all upstream telephony signals within a selected spectral subband in the reverse band to apply a receiver matched filter with a weighted overlap and add circuit, and are then converted to baseband by an FFT circuit. The group receiver provides a serial data stream representing the baseband telephony signals. The baseband telephony signals are processed to derive demodulated telephony signals. The demodulated telephony signals are coupled to the telephony network.
摘要:
A collision handling receiver for use in a data communication network. The collision handling system and method comprises collision handling receivers together with transmitters inserting pseudo-random delays. Accordingly, multiple sources may transmit simultaneous messages to a receiver so that the messages arrive with varying signal levels and times of arrival. The receiver sorts the symbols into separate sequences by grouping together symbols having similar time of arrival. In addition, the receiver retains the sequences with sufficiently reliable symbol detection, for example, when 75% of the symbols in a sequence are detected with sufficient quality. Receiver then ranks the retained transmitters by received signal level and decodes the messages from transmitters with highest received signal level.
摘要:
A multi-channel modulator for the transmission of telephony signals within a broadband communication system. An interpolation module generates processed I and Q signal components by upsampling filtered I and Q signal components. In turn, these processed I and Q signal components output by a filter are passed to a set of channel modulators. Each channel modulator accepts a pair of processed I and Q signal components and, in response, modulates a selected carrier signal with one of the telephony signals to produce a complex modulated signal. An adder module responds to the complex modulated signals by summing the real signal components to produce a real resultant signal, and to sum the imaginary components to produce an imaginary resultant signal. A digital-to-analog converter (DAC) module coverts the real resultant signal and the imaginary resultant signal, which are represented by digital data streams, to analog signals. A transmitter, responsive to the analog signals, transmits the modulated signals within a frequency band of the broadband communications network.
摘要:
A communication system for coupling telephony or other digital networks to a broadband network such as a CATV network. The system transmits a multiplex of telephony signals in the forward band of the broadband network, with individual signals directed to an addressed subscriber. Telephony signals returning from subscribers are modulated onto the reverse band of the broadband network in a frequency division multiplex (FDM). The modulated telephony signals are received at a telephony network interface coupled to the broadband network. A selected plurality of modulated telephony signals are frequency shifted to baseband. The baseband-shifted telephony signals are sampled to generate a plurality of time division multiple access telephony signal samples. A plurality of time division multiple access telephony signal samples are channelized into a serial data stream with a channelizer. The serial data stream is processed with a single digital signal processor (DSP) to derive a plurality of demodulated telephony signals. The demodulated telephony signals are coupled to the telephony network.