A 52Mb/s universal DSL transceiver IC

摘要

A twisted-pair quadrature amplitude modulation (QAM) transceiver IC accommodates data rates from 0 to 52Mb/s. The QAM transceiver is a monolithic mixed signal device implemented in 0.35μm four-level metal single-poly CMOS. The transceiversupports 4-, 16-, 32-, 64-, 128-, and 256-QAM modulation formats and operates at symbols rates as high as 13MBaud. The transceiver chip contains a fully-integrated transmitter, including ATM UTOPIA or synchronous input interface, packet-formatting logic,Reed-Solomon forward error correction (FEC) encoding, a rate-adaptive QAM modulator and a lob D/A converter [11. The receiver portion of the transceiver chip consists of a high-precision 10b A/D converter, a programmable rate QAM demodulator, all-digitalclock and carrier recovery loops, powerful adaptive filters to provide rejection of narrowband interferers and the equalization of severe channel distortions, FEC decoding, ATM UTOPIA or synchronous output interface and an analog phase-lock loop forinternal clock generation from a single crystal reference [2, 3]. The QAM transceiver may be used in applications such as asymmetric digital subscriber line (ADSL) and very high-speed digital subscriber line (VDSL) services.