基于多采样率的复合频率信号频率计设计

Composite Frequency Signal Cymometer Based on Multi Sampling Rate

研究一种20Hz^20kHz双频复合频率的信号频谱在工程技术领域中具有重要应用意义;在对复合频率信号频谱理论分析的基础上,采用了一种多采样率计算复合频率信号频谱的方法,该方法在采用高采样率采集样本进行FFT变换频谱预估计的基础上,利用降采样率的方法再进行一次FFT变换频谱分析,然后结合频谱混叠时信号的频域特征利用预估计的频谱信息计算出高分辨率的频谱信息;该方法计算量适中,可以满足实时性要求;利用TI公司的TMS320F28234DSP作为处理器构建了一个复合频率信号频率计,可以采集输入的复合频率信号并进行多采样率的频谱分析,经测试该频率计可以实时发送复合频率信号的频谱信息到上位机,频率分辨率达到2Hz。

Signal spectrum analysis was widely applied in the field of engineering technology, and it is very important to analyze the fre quency spectrum of composite frequency signal. A new method of spectrum analysis using multi sampling rate was presented, which had high frequency resolution and low computing complexity. The spectrum of 20 Hz-20 kHz composite frequency signal was estimated by FFT algo- rithm using high sampling rate, and refined by down sampling the signal and FFT algorithm. A composite frequency signal cymometer based on TMS320F28234 was designed to sample the composite frequency signal which spectrum was analyzed by multi--sample--rate method, and the results were send to PC in real time which frequency resolution is 2Hz.