Abstract
This paper shows that the wavelet based dead time measurement method, which has been already studied for open loop systems, is also applicable to closed loop systems. The method measures a dead time of an LTI system from a wavelet transform of a cross correlation function between its input and output. At first, we derive the cross correlation function and its cross spectrum for the closed loop case. Next, its wavelet transform is analyzed under certain conditions by using the relation among a wavelet transform of a correlation function and the corresponding spectrum, which we have been already studied. The analysis shows that the dead time is also measurable for the closed loop case although the cross correlation function, the cross spectrum and the wavelet transform have more complicated forms than the open loop case.
