Cable Modem Technology Suppliers
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Introduction
Broadcom
Conexant Systems
Hitachi Semiconductor
Libit Signal Processing
Stanford Telecom
Terayon Communication Systems
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Introduction
A number of companies are providing cable modem silicon solutions, including: Broadcom Corp., Stanford Telecommunications Inc., Conexant Systems (formerly Rockwell Semiconductor), Libit Signal Processing, and Terayon Communication Systems.
Broadcom
Irvine, Calif.-based Broadcom Corp. has outpaced larger rivals to become the leading supplier of silicon in the broadband digital communications market. Cable modem manufacturers Com21, General Instrument, and Motorola have all used a QAM chipset from Broadcom in their proprietary products. Additionally, a long list of DOCSIS cable modem vendors are using Broadcom chips, including 3Com, Cisco Systems, E-Tech, General Instrument, Nortel Networks, Samsung, Sony, and Thomson Consumer Electronics.
Broadcom first offered a three-chip DOCSIS cable modem solution, including the BCM3116 64/256QAM demodulator, BCM3037 16QAM/QPSK burst modulator, and BCM3220 DOCSIS 1.0 cable modem MAC. By the end of 1998, Broadcom integrated these components into a single-chip, dubbed the BCM3300, also adding so-called DOCSIS 1.1 MAC features intended to support IP telephony services.
Conexant Systems
Conexant Systems (formerly Rockwell Semiconductor Systems) is developing an integrated MAC and PHY chip for DOCSIS cable modems.
In December 1998, Conexant began sampling the CN9414, the first single-chip DOCSIS design to include an integrated microprocessor and offer fully-programmable MAC functionality. The CN9414 includes a full DOCSIS physical layer (PHY) with 64/256 QAM demodulator and QPSK/16 QAM burst modulator, 10/100 Ethernet MAC, Universal Serial Bus (USB) transceiver, 40/56-bit encryption engine, and 100-Mbps Media Independent Interface (MII). Conexant has also developed a dual-conversion RF tuner in silicon that it plans to offer with the CN9414.
Conexant will begin sampling the CN9414 to a wider range of customers in May with volume production scheduled for the third quarter of 1999. The CN9414 will carry a list price of $45
in 10,000-unit quantities. Cable modems built with the chip are expected to start shipping early in the fourth quarter of 1999. Conexant believes its programmable MAC will offer a major advantage for cable modem manufactures as they work to migrate from DOCSIS 1.0 to the 1.1 standard this year.
Hitachi Semiconductor
Hitachi Semiconductor Inc. has introduced two DOCSIS-based physical-layer (PHY) transmission chips for cable modems and digital set-top boxes. Hitachi's HD49430F is an integrated 256/64 QAM receiver with forward error correction. Hitachi is also offering a companion upstream chip, the HD49429F, which supports QPSK, 16 QAM and p/4DQPSK modulation.
Libit Signal Processing
Israel-based Libit Signal Processing Ltd. introduced its first 64/256 QAM demodulator chipset in March 1997, the LBT4010C, which is compliant with European DVB/DAVIC standards for cable modems and set-top boxes.
In July 1997, the start-up formed an alliance with Analog Devices Inc. to build DOCSIS cable modem ICs. Libit has developed a single-chip PHY solution (64/256 QAM downstream and QPSK/16 QAM upstream) for DOCSIS client cable modems that Analog Devices is now manufacturing called the LBT4030. Libit offers a separate DOCSIS cable modem MAC chip, called the LBT4230. The company is developing an integrated DOCSIS PHY and MAC chip, called the LBT4040, as well as chipsets for cable modem headend gear.
Toshiba has built CableLabs Certified DOCSIS cable modem with Libit's PHY chip and other vendor deals are in the works. Also, Libit has developed a new headend-based technology dubbed INCA that it claims will increase the upstream noise immunity and data capacity of any DOCSIS cable modem.
Stanford Telecom
Stanford Telecommunications Inc. has historically focused on providing upstream technology solutions for cable modem manufacturers. In December 1996, STEL introduced its next-generation upstream modulator application-specific integrated circuit (ASIC) for cable modems and set-top boxes, the STEL2109. The STEL2109 includes an on-chip digital-to-analog converter and supports three modulation modes: BPSK, QPSK and 16 QAM. Stanford Telecom's earlier STEL2108 upstream modulator was introduced in 1995 and is incorporated into cable modem products from a number of vendors, including Com21 Inc.
Stanford Telecom has developed a single-chip solution, the STEL-2176, to handle upstream (16QAM/QSPK) and downstream (64/256QAM) PHY transmission functions for DOCSIS cable modems.
Terayon Communication Systems
Start-up Terayon Corp. has developed its own cable modem chip solution based on synchronous code division multiple access (S-CDMA) technology, a modulation technique the company claims is so noise immune that cable operators can deploy reliable two-way communication services with less diligent plant clean-up efforts.
The company has built its own cable modem system around S-CDMA, which is based on spread spectrum technology first developed by the U.S. Department of Defense to deal with problems of security and interference in over-the-air communications. In wireless telephony, CDMA technology has found success, but its asynchronous architecture limits throughput when applied to cable data services. Conventional CDMA used for high-speed data can only deliver 2 Mbps per 6 MHz cable television channel. By synchronizing CDMA transmissions (i.e. S-CDMA) Terayon boosts speeds to more than 10 Mbps per 6 MHz channel.
CableLabs is evaluating the use of S-CDMA as an advanced PHY technology for a proposed DOCSIS 1.2 standard.
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