Fast characterization of frequency response in high-speed signal generators with frequency-interleaving technique

This paper presents a frequency interleaving method to correct non-ideal characteristics of wideband signal generators. By effectively segmenting a discrete Fourier transform dataset into frequency-interleaving blocks, the proposed method is computationally more efficient than the conventional method based on Fast Fourier Transform (FFT). In cases the quality of frequency analysis can be improved by zero padding such as characterizing impulse responses, this method is effective because it is possible to interleave two or more FFT results to achieve better frequency resolution. To verify the proposed method, an arbitrary signal generator was tested with a 64 quadrature-amplitude-modulation waveform. Compared with the original signal quality, the proposed method improves the in-band signal-to-noise ratio by 9 dB, and the error-vector magnitude decreases from 2.1%rms to 0.78%rms. In all cases, the computation speed was faster than that of conventional FFT.