摘要
针对MATLAB中两个内建功率谱密度计算函数psd()和pwelch()计算结果迥异的现象,在功率谱密度估计理论的基础上,根据经典的周期图理论和Welch平均周期图方法,通过详细分析源程序,解析计算方法,发现psd()计算的并不是工程单边功率谱密度,而是采样信号双边谱,故与pwelch()结果迥异,另外pwelch()不能对分段信号数据进行预处理。就上述不足提出了相应的改进措施,比较验证表明改进措施行之有效。
Because the results calculated by PSD are quit different from those by PWELCH, the source code is analyzed in detail for these two functions which are used to calculate the power spectrum density in Matlab. On the basis of the theory of power spectrum density estimation, it is found with classical cyclic periodogram and Welch average periedogram what function PSD calculates actually is not power spectrum density used on engineering but double-edge spectrum of collected signals. That is reason for the phenomena mentioned at the beginning of the article. On the other hand, segmental signal can not be pre-processed by function PWELCH. Some ways are proposed to improve those issues, and these actions are proved be effective.
出处
《中国测试》
CAS
2010年第1期93-96,共4页
China Measurement & Test
基金
四川省教育厅重点科研项目(2004A112)
四川省重点学科建设项目(SZD0410-1)
