Jae-seong Shim

Partial-response maximum-likelihood core development for a CD/DVD controller integrated circuit

A new PRML architecture is presented to demonstrate its superiority over the conventional analog channel in a DVD system. In this new architecture, the robustness to the baseline disturbance in the readback signal is emphasized in developing the algorithms for the PLL, digital gain control, asymmetry control, adaptive FIR filter, and Viterbi detector and post processor. In addition, a method of modeling the asymmetrical readback signal is discussed. A new algorithm for the digital PLL is described which does not require the oversampling. A simple method is presented to reduce the asymmetry in the ADC samples. To further improve the sensitivity to the baseline wandering, a Viterbi detector is designed using the difference metric approach and followed by a post processor, which corrects the baseline related errors from the VD. A test chip is fabricated using 0.35 /spl mu/m CMOS technology to demonstrate the performance of the proposed architecture.

Advanced PRML data detector for high density recording

An advanced PRML data recovery system is presented for a high-density recording. The system consists of three major hardware units, which are DC offset compensator, adaptive equalizer, and Viterbi detector with level adaptation scheme. The experiment based on an improved PRML scheme and FPGA hardware realization shows highly reliable performance of data detection up to 35GB recording density. The SER experiment result for 35GB shows that the detector using the proposed PRML yields a result to meet the SER limit of 4.0x10-3 with a margin of 0.45° for tangential and 0.55° for radial tilt. And the base SER marks 7.0x10-5 when there is no tangential and radial tilt error.

Signal quality measurement using channel identification method for high-density optical channel

A new signal quality measurement method for high-density optical read/write system is presented. In this method, the signal quality is expressed in detail as a figure of the coefficients in accordance with channel characteristics.

Fast and accurate frequency detection algorithm for robust timing recovery

A new digital frequency detection algorithm is presented for the fast and accurate frequency detection in optical disc systems. The proposed algorithm is based on the histogram analysis of input data sequences. By using the proposed algorithm, the detection delay is reduced to 1/4 of the conventional delay with the reliable accuracy and the detection resolution is improved by 230 times at the conventional detection delay. Performance improvements can guarantee the robust timing recovery in optical disc systems.