Reaearch Of Error Analysis Technology In Vector Signal Modulation

Digital signal has been applied more and more widely with the rapid development of digital communication. It has a stronger anti-noise capability, higher bandwidth utilization and excellent performance compared with the traditional analog signal. But it also brings challenges to the technology of measurement and analysis. How to measure the performance of broadband high speed digital signal with complex types of modulation has become an urgent problem. Vector signal analysis(VSA), as a new measurement technology, has gradually been a hot research issue. In recent years, significant progress has been made during the research of vector signal analysis technology. And the performance has being improving. However, the technology is still lagging behind in the domestic and related instruments mainly depend on imports. In order to meet the demands of electronic devices in various industries from development, m anufacturing to testing, it is necessary to study and master the core technology of vector signal analysis and develop analysis software with independent intellectual property rights from a long-term perspective.In this paper, we mainly study and implement the error analysis technique of vector signal modulation. Firstly, the vector error analysis model is presented, and its implementation principle and working flow are clarified and the key techniques are discussed. Then we researched the process of the signal from receiving to the rate matching, the synchronization and measurement for the two modulation modes of MQAM and MPSK. Facing with the problem of sampling in broadband high-speed signal, an arbitrary sampling rate conversion algorithm based on looku p table is proposed in rate matching module. The algorithm can effectively solved many problems which still existed in traditional algorithms such as the sampling factor changed inflexibly, low operation rate, large resource consumption, big introduced error, etc. And It gives a detailed analysis of the influence of error. Facing with the problem of carrier synchronization of wideband signal, several common carrier synchronization algorithms are researched deeply, and then we analyze the characteristics of each algorithm and its’ application scenarios. A pre-compensation algorithm is proposed for phase correction of wideband signal. It can solve the problem effectively of the influence in phase estimation caused by residual frequency. Facing with the problem of error measurement and analysis of vector modulation signal, we research the measurement algorithm influencing mechanism of the EVM. And completing the measurements of locus and error which can reflect the error modulation vector. And then make a deep analysis of their specific applications. Finally, we design and implement a VSA measurement and analysis system for the MPSK and MQAM, which is based on the findings above. The result of test by the actual data show that the performance of the VSA system we designed is similar to 89600 VSA software of Agilent.