Title :
Performance evaluation of an adaptive RAM-DFE read channel
Author :
Bednarz, P.S. ; Sands, N.P. ; Modlin, C.S. ; Lin, S.C. ; Inkyu Lee ; Cioffi, J.M.
Author_Institution :
Inf. Syst. Lab., Stanford Univ., CA, USA
fDate :
3/1/1995 12:00:00 AM
Abstract :
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. Implementational 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/sup -8/ BER with the probability of a 30 bit burst, given a single decision error, to be less than 10/sup -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.<>
Keywords :
Markov processes; adaptive equalisers; decision feedback equalisers; hard discs; magnetic recording; random-access storage; 0.2 dB; 54 Mbit/s; Markov model; adaptive RAM-DFE read channel; bit error rate; burst; decision error; decision feedback equalizer; error propagation; loss; magnetic hard-disk drives; partial response maximum likelihood detector; spin-stand; thin-film head; Bit error rate; Degradation; Equalizers; Feedback; Hard disks; Loss measurement; Maximum likelihood detection; Predictive models; Propagation losses; Testing;
Journal_Title :
Magnetics, IEEE Transactions on
