ANISOTROPY OF SURFACE ROUGHNESS - Centrum Textil

60Spectral504030analysis20100-1 0Expression of signal R(x) by the Fourier series of sineand cosine wave. The Fourier Transform is conversion of datafrom series according to x to the series of frequencies ,RF∑( ω ) = R ( x ) * exp( − i * ω * x )S =-2 00 500 1000 150022 2( ω)= DRF * conj(DRF) / L abs(DRF)/ Lω = 2π* k /( M * L)conj(.) denotes conjugate vector.For discrete data the fast Fourier Transform (FFT) leads totransformed complex vector DRF.Vector DRF may be used for creation of power spectral density( PSD) S(ω)