Frequency response functions (FRF) are the most fundamental data for t
he frequency domain identifications of the dynamic characteristics of
structural systems. Several techniques have emerged for the estimation
of FRF so as to minimize the effect of measurement noise. This paper
presents an improved method for estimating FRFs. The new FRF estimator
takes the weighted average of two conventional estimators, H1(f) and
H2(f), utilizing the characteristics that H2(f) gives a more accurate
estimate at resonance, while H1(f) yields a better result at antireson
ance. An exponential weighting function is proposed, and the parameter
of the weighting function is determined by minimizing the resolution
bias error of the FRF over the significant frequency range. Based on t
he estimated FRFs, the modal parameters of the structural systems, suc
h as, natural frequencies, damping ratios and mode shapes, are estimat
ed. The effectiveness of the proposed method is investigated through n
umerical and experimental studies. The estimated results indicate that
the proposed estimator gives more accurate results than other estimat
ors.