On Band Stitching for Wideband Vector Measurements With Vector Signal Analyzers

As the bandwidth of radio signals increases significantly over the evolution of communication systems, the analysis bandwidth of many current instruments becomes insufficient. In this article, we study analysis bandwidth extension using the so-called band stitching. Specifically, we propose a two-step delay estimation method, which combines the cross correlation and an additional refining step to resolve the timing impairment between different sampling branches in postprocessing. We verify the method with a sequential measurement setup, using vector signal analyzers (VSAs). The result shows the necessity of conducting the refining step for getting a more accurate delay estimate to successfully recover the original wideband signal. Besides, a good agreement is found between the stitched data and the reference data in terms of the waveforms and error vector magnitude (EVM), which shows the effectiveness and robustness of the proposed calibration method in practice.