多阶光盘系统中帧同步信号的自适应检测

多阶光存储是提高光盘存储容量和数据传输率的重要途径。帧同步信号在多阶光盘的重放系统中起着很重要的作用。分析了实际多阶存储系统中帧同步信号的特征和信号检测的特点,提出了一种自适应检测帧同步码的方法。实验结果表明,该方法的精度可以满足系统的需求。     

A new tracking error detection method using amplitude difference detection for signal waveform modulation multi-level discs

The sub-land/sub-pit affects the characteristic of the tracking error signal which is generated by the conventional differential phase detection (DPD) method in the signal waveform modulation multi-level (SWML) read-only disc. To solve this problem, this paper proposes a new tracking error detection method using amplitude difference. Based on the diffraction theory, the amplitude difference is proportional to the tracking error and is feasible to be used for obtaining the off-track information. The experimental system of the amplitude difference detection method is developed. The experimental results show that the tracking error signal derived from the new method has better performance in uniformity and signal-to-noise ratio than that derived from the conventional DPD method in the SWML read-only disc.     

Improved partial response maximum likelihood method combining modulation code for signal waveform modulation multi-level disc

In this paper, we describe an improved adaptive partial response maximum likelihood （PRML） method combining modulation code tbr signal waveform modulation multi-level disc. This improved adaptive PRML method employs partial response equalizer and adaptive viterbi detector combining modulation code. Compared with the traditional adaptive PRML detector, the improved PRML detector additionally employs illogical sequence detector and corrector. Illogical sequence detector and corrector can aw）id the appearance of illogical sequences effectively, which do not follow the law of modulation code for signal waveform modulation multi-level disc, and obtain the correct sequences. We implement the improved PRML detector using a DSP and an FPGA chip. The experimental results show good performance. The higher efficient and lower complexity can be obtained by using the improved PRML method than by using the previous PRML method. Meanwhile, resource utilization of the improved PRML detector is not changed, but the bit error rate （BER） is reduced by more than 20%.     

蓝光高密度光盘驱动器中聚焦误差特性分析

高密度数字视盘(HD-DVD)是一种新型蓝光存储技术，可以满足数字高清视频节目的播放要求.介绍了用于HD-DVD驱动器中的刀口法调焦方案，基于菲涅耳公式和标量衍射理论，推导了刀口法调焦的HD-DVD驱动器中聚焦误差信号与离焦量之间关系的计算模型.应用该计算模型，分析了不同离焦量时探测器上光强分布情况.计算得到的聚焦误差信号与离焦量之间的关系曲线与实验测得的“S型”曲线相一致，证明了计算模型的正确性.进一步分析了正焦点时由于记录符调制而引起的聚焦误差的干扰信号，计算结果表明这种干扰的强度小于4.5%.分析表 关键词： 光存储 刀口法 聚焦误差 标量衍射     

光盘存储读出信道的实现

通过构建适合于硬件电路实现的读出信道数学模型以及对光存储系统中存在的噪声、抖晃和扰动的分析,在FPGA(Field programmable gate array)硬件平台上,实现了对任意二阶至四阶记录光盘读出RF(Radio frequency)信号的模拟实时连续输出。在信道模拟的硬件算法设计中,采用了四倍频的方法和基于ROM(Read-only memory)查找表的方法实现了100Mbit高速情况下的卷积运算。设计结果得到了逼真的网眼图,验证了模型的正确性,且已作为光盘系统后续信号处理模块的信源,加快了光盘系统研制开发的步伐。     

一种新的多阶只读光存储方法的仿真分析和实验验证

提出了一种波形调制的方法,在原有记录符中加入一个短坑或短岸,在读出信号上产生一个可辨识的"扰动",从而对读出信号波形产生调制.用简化的光刻模型和基于角谱分解的读出模型,对该方法在DVD系统上的坑形和读出信号进行了仿真.仿真结果确定了各个游程可实现的阶次和各个阶次的刻写参量.对典型游程6T和11T进行了实验,读出信号与仿真结果相吻合,并分别得到了小于1×104和1×10-5的阶次误码率.实验结果验证了该方案的实际可行性.     

用于多阶光盘游长检测的PRML系统

对用于多阶光盘游长检测的部分响应最大似然（PRML）检测器的设计和实现进行了详细研究。分析了多阶光盘的编码形式，并将编码进行简化以减小维特比检测器的路径数和运算复杂度。为了提高PR均衡器和维特比检测器的性能，分析了目标PR多项式系数和记忆长度的选择。阐述了多阶光盘游长识别的维特比算法，对算法进行仿真，分析了维特比算法的识别效果，并与与传统识别算法的效果进行了比较。     

Analysis of differential phase detection signal of a novel multi-level read-only disc

To improve the tracking servo performance, a novel signal waveform multi-level （SWML） read-only disc realized on the digital versatile disc （DVD） platform is presented. The characteristic of the differential phase detection （DPD） signal of the SWML read-only disc is analyzed both in theory and experiment. The amplitude of the DPD signal of the SWML read-only disc in an open tracking servo loop is about 2/3 of that of the DVD read-only disc. The uniformity and symmetry of the DPD signal of the SWML read-only disc are similar to those of the DVD read-only disc and better than the former multi-level run-length limited （ML-RLL） read-onlv disc.     

Theoretical and experimental analyses of recording mark microstructures in signal waveform modulation optical disc

In this paper,we propose a dynamic mastering process model for signal waveform modulation (SWM) optical disc.To form the ideal microstructures and solve the problems in the SWM master manufacturing process,we use this model to simulate the three-dimensional mark profiles in the SWM read-only disc.The simulated micro-patterns of recording pits and lands are employed to optimize the writing strategy and provide a quantitative basis for manufacturing the sub-pits and sub-lands.The simulation mark profiles are compared with the experimental ones,which are produced with the optimized writing strategy parameters.Comparison results demonstrate that the simulated profiles are highly consistent with the actual ones.