Properties of Fourier spectrum of the signal, generated at the accumulation point of period-tripling bifurcations

Universal regularities of the Fourier spectrum of signal, generated by complex analytic map at the period-tripling bifurcations accumulation point are considered. The difference between intensities of the subharmonics at the values of frequency corresponding to the neighbor hierarchical levels of the spectrum is characterized by a constant $\gamma=21.9$ dB?, which is an analogue of the known value $\gamma_F=13.4$ dB, intrinsic to the Feigenbaum critical point. Data of the physical experiment, directed to the observation of the spectrum at period-tripling accumulation point, are represented.