通过复解析带通滤波构造时域信号的解析信号，消除因时域实信号作FFT时由于时域截断产生的负频率成分能量泄露对正频率成分的干扰，从而提高自由衰减振动信号频谱校正精度。仿真分析及工程实测结果表明，当各个固有频率相隔较远时，校正精度很高。但在各阶固有频率靠得很近时不能直接使用这种方法。

A new method is proposed in this paper to improve the precision of spectrum correction of damped free vibration response based on frequency-domain. The principle of this method is that a length of continuous, free, damped vibration signal is sampled and its analytical signal is constructed, then N points Fast Fourier Transform (FFT) is performed to the analytical signal from its starting data point and the (L+1)-th data point. Finally, the modal parameters are calculated by the parameters of two corresponding peaks of amplitude spectrums. This method can reduce the spectral leakage of negative frequency component caused by FFT. Results of Simulations show that the precision of spectrum correction can be rather high when the natural frequency of each modal parameter is far from the others. However, the method cannot be used if one natural frequency is very close to the others or the modal coupling is very serious.