Frequency Response Function measurements using concatenated data records

This paper presents a nonparametric method to measure the frequency response function (FRF) of a linear dynamic system that allows a series of sub-records to be concatenated in one long data record without suffering from the leakage and transient errors. The method combines data blocks (of different length) 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 (SISO) and multiple-inputmultiple-output (MIMO) systems. The results are illustrated on simulations and experimental data.