Walter Y. Chen

A direct equalization method

The unshielded twisted pair can be used as a transmission media for local distribution networks. To maintain a high transmission throughput, an analog or a digital adaptive channel equalizer is usually required in the receiver to minimize the effect of inter-symbol interference. Under the observation that the high sampling rate high precision A/D and subsequent digital adaptive signal processing is an expensive approach, a direct equalization method, where the equalizer is implemented in the transmitter, is proposed for symmetrical twisted pair transmission channels. This direct equalization method can also be applied to the analog equalization approach for reduced system complexity.

TI DSP implementation of a medium speed DSL (MDSL) for multimedia applications

The high performance general purpose digital signal processor (DSP) provides a cost efficient solution for a broadband digital subscriber line (DSL) transceiver. A DSL modem with a transmission throughput between 400 kbps and 2 MOPS operating over most of the existing telephone subscriber loops has been implemented on a single TI TMS320c548 DSP for consumer multimedia applications such as Internet access. Except the analog front end (AFE), all the discrete multitone modem (DMT) algorithms are implemented with DSP software. The DSP based software DSL modem also provides a convenient interface to Microsoft point-to-point protocol (PPP) for network access.

Internet gateway for long-distance 1394 home network

An experiment has been conducted with emphases on the home network transmission layer and the Internet gateway device. The IEEE 1394 is chosen as the transmission mechanism for its capability of handling both isochronous and asynchronous transmissions. To cover the reach of a conventional home, a 1394/100BaseTX converter has been developed to carry the 1394 signaling protocol over a Category 5 unshielded twisted pair cable with a maximum point to point distance of 100 meters. A gateway device to the Internet is designed and configured based on a PC. The gateway consists of a 1394 transceiver with PCI interface, a digital subscriber line transceiver, and Windows based networking software. This paper focuses on the general long distance 1394 transceiver hardware, gateway system configuration and software architecture. Issues such as DHCP, private IP address, and DNS are also discussed.