Abstract: Continuous bands exsit in the spectrum of chaos signals because of the pseudorandomicity of chaos. But the cause and characteristics of continuous bands are neglected. Based on the solutions of two kinds of duffing equations, a large kind of chaos solution is found, which has the same characteristics in frequency domain, then the cause and characteristics of continuous bands are studied. The position and the shape characteristics of continuous bands are summarized, as well as the relations between different continuous bands. The analysis result of chaos solutions by complex analytical wavelet shows the modulation characteristic and modulation comparability of chaos, which redounds to reveal the cause of continuous bands for chaos solution and the cause of the comparability among different frequency bands for one chaos solution. Furthermore, the modulation characteristic and the modulation comparability are combined with the strange attractor to reveal the regional concentration and the similarity among shapes on different parts of the strange attractor.

Key words: Amplitude spectrum, Chaos, Complex analytical wavelet, Continuous bands, Modulation, Strange attractor