The signal shapes appeared in the noise excitation spectroscopy are st
udied. This spectroscopy is based on broad-band excitation with noise
light, wave-form correlation, and Fourier analysis. The Zeeman signals
of the excited state of the D-1 transition in Rb atoms were observed,
The Fourier spectra obtained from the auto- and cross-correlations of
excitation and emission wave forms are compared and are analyzed by a
linear response theory.