Research And Development On Measurement System For Jitter Of High-Speed Optical Discs

As the main media, the CD and DVD discs are well used in the storage of data, distribution of programs and the entertainment of video and audio. To evaluate the quality of discs, jitter which affects the recovery of the data stored in the discs is used as one of the most important parameters, especially when discs are worked at a high speed. This thesis presents a measurement system for jitter of high-speed discs upon the research of jitter. The system has a character of high resolution, high reliability, compact architecture, simple operation and low cost. The thesis is part of the National Key Project 973 named "High-Density and High-Access-Speed Optical Data Storage System". Firstly, the essential question of jitter measurement is discussed. A novel method called Two-Step Cascading Delay Line is described based on the present methods and technologies for precision measurement of time interval. Secondly the circuit architecture of the system is carefully studied and designed. The core module and assistant modules of jitter measurement are implemented using a single FPGA chip and VHDL programming language, and data transfers are carried out between circuit and computer via PCI bus with a PCI interface chip. Then the application software of the system is developed. The device driver and user interface are programmed, and two measurement interfaces are provided. The calibration of the system is also discussed. At last, the experiments are designed and processed to evaluate the system. The testing results indicates that the system has internal jitter of 40 ps or lower with a single-shot resolution of 75 ps and a multi-shot resolution of ~ 5 ps, and the system can be applied for jitter analysis of CD at a maximum speed of 60X and DVD at 12X.