Satoru Higashino

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

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).

Hybrid equalized partial response path-feedback maximum likelihood toward higher density Blu-ray disc

Recently, high density optical recording systems like BD (Blu-ray disc) have been standardized regarding a PRML (partial response maximum likelihood) signal processing technology, which has been thoroughly investigated on high density magnetic recording channels for many years. In order to gain a margin of optical disc drives, PFML (path-feedback maximum likelihood), which is also known as adaptive Viterbi, has been also developed in recent years. In this paper, we propose a new signal processing system, which equalizes the waveform causally, enhances the performance of the PFML detector and provides a stable PLL (phase locked loop) towards much higher density formats than standard BDs.

Performance of trellis coded class-1 partial-response

The performance of trellis-coded class-1 partial-response (TCPR1) is presented. A rate 8/10 partitioned matched-spectral-null (MSN) code for class-4 partial-response (PR4) is applied to class-1 partial-response (PR1) in this paper. A method to eliminate quasicatastrophic (QC) sequences on PR1 detector trellis is described. The performance of 8/10TCPR1 was better than that of 8/10TCPR4 at user density over 2.2 in simulation and much improved compared with 8/10PR1ML in practice. The conditions under which PR1 has performance advantages over PR4 are also presented.

Hybrid Equalized Partial Response Path-Feedback Maximum Likelihood for 35.4 GB Blu-ray Disc ROM

The decoding method with larger margin has been required according to the recent high density optical recordings. Since the optical reproduced signal has a strict cutoff of modulation transfer function (MTF), the high linear density equalization will cause the equalization error. In such a case, adaptive Viterbi [rf1,rf2,rf3] has been investigated as a decoding method which compensates tangential inter-symbol interference (ISI) and the scanty high frequency components. This fundamental theory is based on path feedback Viterbi detection. [rf4] We have developed hybrid equalized partial response path-feedback maximum likelihood (HEPR-PFML) which compensates the scanty frequency components more efficiently than conventional adaptive Viterbi. By using this system, the decoding performance is not only improved, but phase locked loop (PLL) will be stable because of the clear timing error information. We will show the experimental results for the higher density 35.4 GB Blu-ray Disc ROM (BD-ROM) than standard linear densities.

Performance of TCPR in magnetic azimuth recording

The 8/10 DC-free code was developed into 8/10-PR1ML in azimuth recording. We previously discussed the performance of the 8/10 MSN code for Class 1 partial response (8/10 TCPR1) (1997). In this paper, TCPR1 and TCPR4 are applied to azimuth recording channels with cross-talk noise and white Gaussian noise. A simulated performance of several different user densities, azimuth angles and track pitches was carried out and the results presented. After determining suitable azimuth recording parameters for TCPR, we found a large off-track margin can be achieved on a removable medium such as magnetic tape.

A Reduced High Dimensional FDTS For Magneto-Optical Recording

FDTS (Fixed Delay Tree Search) sequence detection using metric calculation is demonstrated. FDTS with a long tree depth is performed using a High Dimensional Signal Space Detector. We propose a new HD (High Dimensional)-FDTS employing a reduction algorithm under conditions of a certain minimum RLL (Run Length Limitation) of code and with ISI (intersymbol interference). We made sure that the HD-FDTS minimum distance taking account of the RLL code was close to that of a Viterbi decoder. The decoder circuit is small and high speed and has a reasonable noise margin for an ideal equalized wave with AWGN (Additive White Gaussian Noise). The HD-FDTS may be applied to PLL (Phase Locked Loop) and AGC (Automatic Gain Control) because of the short decoding delay.

Partitioned Linear Interpolated Timing Recovery for Optical Discs

We have developed the partitioned linear interpolator for interpolated timing recovery (ITR), which provides the implementation of the ITR with a small memory table and the sufficient performance for optical discs.

Matched Spectral-Null Code with Run-Length Limitation for Optical Recording Channels

High track-density recording and multi-layer recording have been investigated for large capacity optical recording discs. In this case, the recorded data will be reproduced under the low Signal-to-Noise Ratio (SNR) condition due to crosstalk from the adjacent tracks or the other layers, and robust data detection will be required. In this paper, a novel Matched Spectral-Null (MSN) code providing the property of Run-Length Limitation (RLL) was described considering the optical recording channels. Trellis Coded Partial Response Maximum Likelihood (TCPRML) employing the MSN code with RLL was also proposed for the data detection method enhancing the minimum Euclidian distance. The detection performance was estimated through the simulation model, which emulates the optical recording channels based on the Blu-ray Disc (BD) specification.

A Parallel Architecture of Interpolated Timing Recovery for High-Speed Data Transfer Rate and Wide Capture-Range

High data transfer rate has been demanded for data storage devices along increasing the storage capacity. In order to increase the transfer rate, high-speed data processing techniques in read-channel devices are required. Generally, parallel architecture is utilized for the high-speed digital processing. We have developed a new architecture of Interpolated Timing Recovery (ITR) to achieve high-speed data transfer rate and wide capture-range in read-channel devices for the information storage channels. It facilitates the parallel implementation on large-scale-integration (LSI) devices.