A 30-MHz Trellis Codec Chip for Partial-Response Channels

We present a rate 8/10 matched-spectral-null (MSN) trellis codec chip which can increase noise tolerance in partial-response channels applicable to digital magnetic recording. The Viterbi detector in this codec features an area-efficient pipelined architecture and a modulo metric normalization technique. The chip was implemented in a 1.2-μm CMOS process with a die size of 22 mm2. It offers a 12-Mb/s data rate when operating at 30 MHz. Experimental results verified the predicted coding gain of 2.8 dB relative to the uncoded system at a bit-error rate of 10 -7. © 1991 IEEE