The aim of this paper is to prove that the derivative of the log of capital flow understood as price times volume advances the derivative of log of the price. A certain concept of signal processing using linear filtering has been proposed to conduct the research.

In this paper the problem of cycles existence in capital markets is addressed. A spectral analysis algorithm, which reduces signal-to-noise ratio, is proposed to derive cycle periodograms for the yield function of DJIA, WIG~20, and NIKKEI 225 indices. Peaks of the the periodograms provide premises to postulate the existence of some possible cycles. The 3.5 year periodicity in all 3 indices, which can be related to Kitchin cycle...