Iterative decoding of greater than 100-Gb/in2 recordings

As signal-to-noise ratio decreases from ever-shrinking bit cells, advanced signal processing has played a key role in enabling system performance. In this paper, spin-stand head/media waveforms from greater than 100-Gb/in² recordings were captured and processed through a software channel using a turbo product code with single parity check (TPC/SPC). Up to 200 Mb of user data were captured from each on-track or off-track location to characterize the bit-error rate (BER) performance. Almost four orders of magnitude BER improvement have been observed through TPC/SPC compared with the uncoded Viterbi algorithm. Typical iteration histogram and burst-error profiles are analyzed. Performance loss from real waveforms compared with the additive white Gaussian noise simulations are also discussed.