Asymmetry Compensation by Nonlinear Adaptive Partial Response Equalizer for 31.3 GB Blu-ray Disk ROM

Abstract

We investigated a nonlinear adaptive partial response equalizer for the asymmetry compensation of a 31.3 GB higher linear density Blu-ray disc read only memory (ROM) with a 16% asymmetry. A second-order adaptive Volterra filter approximately equalizes a nonlinear signal into a linear one. We reduced its calculation complexity to design a digital circuit in optimum hardware resources by the result of computer simulations. Then we designed an adaptive Volterra filter on an FPGA evaluation board for bit error rate measurements. Finally, we determined that an adaptive Volterra filter has a capability to obtain improved bit error rates by signal linearization in a conventional Viterbi detector for PR(1221).

Study of Interpolated Timing Recovery Phase-Locked Loop with Linearly Constrained Adaptive Prefilter for Higher-Density Optical Disc

“…In general, MMSE ITR PLL with a linearly constrained adaptive Volterra filter read channel includes four main technical components: (i) ITR PLL, [4][5][6] (ii) MMSE adaptive filter placed before ITR PLL, 5) (iii) AVF, 12) and (iv) LCAF. 10,11) In this paper, we concentrate on the theory of (iv) because the references of (i)-(iii) are very well described articles and we can refer to these references easily.…”

“…The sampled read back signal envelope is adjusted by auto-gain control (AGC), and the signal is adaptively equalized by the asynchronous sample LCAF and second-order AVF. 12) Both LCAF and AVF are asynchronous sample adaptive equalizers, and asynchronous fractional LMS errors are calculated by the ITR À1 error generator 5)…”

“…The phase error is calculated by the decision-directed timing error detection method 6,13,14) for the PR-equalized signal. The fractional sample second-order AVF 12) is placed before the interpolator of ITR PLL. The output of AVF is depicted as…”

“…We utilized this LCAF algorithm to improve stabilities of the MMSE ITR scheme by fixing the 8T component update of the adaptive filter. We also used a channel-rate-asynchronous adaptive Volterra filter (AVF) 12) for asymmetry compensation placed before ITR PLL in order to improve the phase error calculations degraded by nonlinear read back signals. In addition, we developed this read channel system on the FPGA evaluation board.…”

Bit-Error-Rate Evaluation of Super-Resolution Near-Field Structure Read-Only Memory Discs with Semiconductive Material InSb

“…6) DF-PRML is one of the nonlinear signal processing techniques to detect recorded data from readout signal, compensating signal variation for each bit pattern. Nonlinear-type signal processing techniques such as DF-PRML, adaptive PRML, 7) Volterra filter 8) compensating asymmetry of readout signal, and time shift are effective, but they require a relatively large circuit.…”