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| 摘要: |
| 以非正弦周期信号为例，对常用频谱分析方法进行了仿真，分析了混叠失真，频谱泄漏及抗混叠滤波器对谐波幅度与相位的影响。指出了在分析精度一定的情况下，滤波器的阶数，截止频率及采样频率之间的相互制约，这三者中当某一项确定后，根据误差公式可以合理的设计另外两项，结合具体情况就可得到低通滤波器与采样频率的最佳组合，通过定量计算各种因素引入的误差，提出了一种精密的频谱分析方法：即用宽带低通进行抗混叠滤波，根据基波频率调整采样速率以及用过采样来减小混叠失真。 |
| 关键词: 精密频谱分析系统 设计 宽带低通 调整采样频率 过采样 数字信号处理 |
| DOI： |
| 分类号:TM935 |
| 基金项目: |
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| Design of precise frequency spectrum analysis system and its implementation based on DSP |
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LI Fen-hua 1 PAN Li-dong 1 CHANG Tie-yuan 1 LI Xue-tao 2
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| Abstract: |
| With the non-sinusoidal periodic signal,the general method of frequency spectrum analy-sis is simulated.The effect of promiscuous distortion,frequency leaking and anti-promiscuity filter on the amplitude and phase of harmonic is analyzed.It is illustrated that,under a given precision,there are certain relations among the order of filter,cut-off frequency and sampling rate.When one is fixed,the other two can be designed with the error equation to obtain the best combination of low-pass filter and sampling rate accordingly.After quantitative evaluation of the errors induced by different factors,a precise method of frequency spectrum analysis is presented.It reduces the promis-cuous distortion by applying anti-promiscuous broadband LPF and over sampling,and adjusting the sampling rate according to the fundamental frequency. |
| Key words: broadband LPF,sampling rate adjusting,over-sampling,DSP |
