Frequency Response Function Measurements Using Concatenated Subrecords With Arbitrary Length

This paper presents a nonparametric method to measure the frequency response function of a linear dynamic system that allows a series of subrecords with arbitrary length to be concatenated in one long data record without suffering from the leakage and transient errors. The method combines data blocks (of different lengths) into a single record, resulting in an increased frequency resolution. The analysis is based on the recent insight that leakage errors in the frequency domain have a smooth nature that is completely similar to that of initial transients in the time domain. The method is applicable to both single-input-single-output and multiple-input-multiple-output systems. The results are illustrated on simulations and experimental data.