Signal processing design for an ADSL high speed equalizer

An asymmetric digital subscriber line (ADSL) is an emerging technology for the transport of video services or other asymmetric high bit-rate services over the copper local loop plant. This paper describes the design and implementation of a high speed equalizer for an ADSL research prototype. This equalizer contains two complex adaptive 32-tap equalizers, and is capable of processing QAM or carrierless amplitude/phase (CAP) modulation signals up to 1 MBaud in speed. Implementation is via off-the-shelf fixed and programmable DSPs, with a resulting throughput in excess of 300 MIPS. Experimental results are presented indicating a reach of 18 kft of twisted copper pair for the system.<
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