| Known as eyes of engineers, Oscilloscopes can help researchers to measure the quality of the signal intuitively in the field of communication.In recent years, high-speed serial communication technology has been widely used, and engineers’ demands on serial signal measuring instruments are increasing,which leads to the emergence of the digital fluorescent serial signal analyzer. As the latest series of digital oscilloscopes, the digital fluorescent serial signal analyzer has a wide variety of powerful functions, for example, it can display signals in real-time, storage waveform data and analyzes the complex three-dimensional information of signals.Although the digital fluorescent serial signal analyzer has made several technique breakthroughs in the field of measurement, there are still some short-comings, such as high cost, non-portability, poor function expansibility and difficulty in the iteration. So the interest of researchers has been turned to off-line signal analysis software based on PC, which can make full use of the advantages of the PC processor. And by analyzing and processing the saved off-line signal waveform data by software, the desired measurement result can be obtained more efficiently.Off-line signal analysis software can be installed in the computer and run directly, analyze and measure off-line waveform data saved by oscilloscopes anywhere and anytime without real-time requirements and be very portable. The software can meet the specific needs of different users in function expansibility and be updated easily. Users can upgrade the software directly on the system, leading to the cost reduction of measuring instruments development, update, and maintenance.This thesis is supported by the research of digital serial signal analyzers, the National key foundation for exploring scientific instruments of China. The purpose of this thesis is to study and implement an off-line signal analysis software based on LabVIEW. The software has three functional modules: measurement of the waveform’s basic parameter, eye diagram analysis, and SDH protocol analysis. The specific work and the innovation of this thesis include the following aspects:1. In this thesis, the principles and algorithms of eye diagram are introduced, including the principle and implementation of eye diagram recovery, the meaning of eye pattern and the generation algorithms of eye pattern template for STM-1 signal corresponding to ITU-T G.957 standard, the definition and measurement algorithms of eye parameters such as eye height, eye width, rise time / fall time and so on.2. This thesis studies the content of SDH protocol and the transmision structure of SDH frame, the significance of each byte in segment overhead(SOH) of the SDH, and the algorithm of reading SOH in SDH frame from STM signal.3. The process of clock data recovery using phase-locked loop technique is studied. The principle, scheme design and the practical algorithm of lead-lag phase-locked loop in software are discussed in detail.4. The above-mentioned functions are realized in LabVIEW by programming. The eye diagram recovery of the off-line signal waveform data are realized, and the eye diagram template of the STM-1 signal conforming to ITU-T G.957 standard are generated. The software clock data recovery function has been completed. And the functions of reading the segment overhead of the STM-1 signal and displaying them in hexadecimal have also been realized. |
