Robust broadband periodic excitation design

This paper considers a rather practical problem arising when inexperienced users misuse the (otherwise well designed) periodic broadband excitation signals during the measurement or signal processing phase of an identification process. Using a fractional period of the excitation signal instead of full periods may affect not only the precision because of the well known leakage effect, but may cause a serious loss of information on the measured system as well. The power of the excitation signal in certain frequency bands may be much lower (30-40 dB) than it would be expected, and thus the measurement in a noisy environment may give poor result. A solution is presented here to make periodic broadband (multisine) excitation signals more robust against such misuse. The suggested solution is analyzed, and the theoretical results are verified by practical examples.