通过对时间交替采样(Time—interleaved ADC,TIADC)理论和下变频快速傅里叶(Fast Fourier Transform,FFT)的研究,提出一种复用FFT结构的自适应TIADC频谱分析设计方案。该方案首先通过四通道ADC进行时间交替高速采样,并采用频域互谱法估计时延误差,利用Farrow滤波器进行自适应校正;然后对采样数据作下变频处理,并复用F丌模块,实现高速采样的频谱分析;最后通过FPGA实验验证,证明自适应TIADC的频谱模块设计不仅能准确反映采集信号频谱信息,而且硬件资源开销相对减小。
A design of spectrum analyser with adaptive time compensation is proposed by the study of time-interleaved ADC theory and digital down conversion FFT algorithm. Firstly, high-speed data are obtained by four-channel ADC sampling, frequencydomain cross-spectral is used to estimate time mismatch deviation and correcte delay deviation with Farrow structure's fractional delay filter. Then sampling data is processed by digital down conversion, and FFF module is reused to obtain spectrum information of signal. Finaly, the results of FPGA experiment show that time-interleaving spectrum analysis can not only reflect the acquisition signal spectrum information accurately, but also decrease hardware resource expenses in relatively.