Performance Evaluation of an Adaptive RAM-DFE Read Channel

Philip S. Bednarz, Nicholas P. Sands, Cory S. Modlin, Susan C. Lin, Inkyu Lee, John M. Cioffi

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The bit error rate (BER) performance of a 54 Mbps RAM-Decision feedback equalizer (RAM-DFE) read channel for magnetic hard-disk drives is evaluated. A controlled test environment allows comparison of measured BER to the performance predicted by a model of the equalizer and channel. Imple-mentational effects are found to degrade performance 0.6 dB in relation to theory. Measurements also show a 0.2 dB loss due to error propagation at 10-8 BER with the probability of a 30 bit burst, given a single decision error, to be less than 10-5. A simple Markov model of the error propagation process corroborates the findings. Finally, the RAM-DFE read channel is compared to a partial response maximum likelihood (PRML) detector of similar complexity on a spin-stand running with a thin-film head and media. The RAM-DFE exhibits a measured 25 fold decrease in BER over the PRML system on a wide range of densities.

Original languageEnglish
Pages (from-to)1121-1127
Number of pages7
JournalIEEE Transactions on Magnetics
Issue number2
Publication statusPublished - 1995 Mar
Externally publishedYes

Bibliographical note

Funding Information:
Manuscript received June 17, 1994; revised September 16, 1994. N. Sands is now with Philips Semiconductors, Sunnyvale, CA. This work was made possible through grants from Samsung, Philips Semiconductors, and Quantum Corporation.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


Dive into the research topics of 'Performance Evaluation of an Adaptive RAM-DFE Read Channel'. Together they form a unique fingerprint.

Cite this