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 μm CMOS technology to demonstrate the performance of the proposed architecture.
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