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).

We describe the format of the 22.5 GB rewritable digital-video-recording (DVR) system. The format is based on an objective lens with a high numerical aperture (NA=0.85), a thin cover layer (0.100 mm thick), and a blue-laser diode (λ=405 nm). We discuss experimental verification of the format and possible future extensions. The DVR system is well suited to be the basis of a third-generation optical-recording family for high-definition video recording.

We discussed data error propagation due to dust on disk surfaces in cases of various cover coat thicknesses and dust sizes. We proposed a system durability gauge K-value and discussed abilities of error correction codings (ECCs) by using a measured Kvalue. A measured dust particle distribution was shown, and error propagation was calculated for thin-cover cases with different K-values. We found that 0.6-1.2 mm cover coat disk systems are free of errors due to dust and a thin-cover coat disk is not always worse. In the thin-cover coat systems, it is particularly necessary to increase K-value and to optimize ECC schemes.

No abstract

No abstract