A high-accuracy harmonic analyzer prototype eased on FAFT

FFT is widely used for determining the spectra of band-limited and non-band-limited signals from their sampled data. However, FFT is subject to the sampling theorem and there is the possibility of some forms of aliasing error and leakage error as well. With a 12-bit A/D, a high-accuracy harmonic analyzer prototype based on fast anti-aliasing Fourier transform (FAFT) is developed. Unlike FFT-based harmonic analyzer, FAFT based analyzer does not need the anti-aliasing filter, and thus the transfer errors of anti-aliasing filter are avoided. Main error sources of the prototype are quantization noise, transfer distortion of S/H circuit as well as the effects of non-zero width sampling pulse including its jitter It is shown that dynamic sampling accuracy of the prototype is better than O. 1% over a dynamic range more than 20dB.<>