Version: 1.7.0 (using KDE 4.0.1) Installed from: Unspecified Compiler: Fedora 6 OS: Linux Problem: Use both Octave and Kst to plot the amplitude spectrum of the following function f=(sin(5*pi*t)).^4+(cos(5*pi*t)).^5,where t ranges from 0 to 3 In Kst, the spectrum is set up as shown below: The FFT length is 2^7 The sample rate is 265.99 The resulting spectrum is not viewed by an apodization function. The mean is not removed In Octave, the following is calculated before plotting the spectrum: N=2^7; t=linspace(0,3,N); %t is a vector with N linearly spaced elements between 0 and 3 Ts=t(2)-t(s); %sampling period Ws=2*pi/Ts; %sampling rate = 265.99 W=Ws*(-N/2:(N/2)-1)/N; %frequecny vector
Created attachment 25459 [details] This kst file has the plot of the amplitude spectrum described in bug report
Created attachment 25460 [details] The resulting amplitude spectrum from the Octave
Created attachment 25462 [details] the mfile used to plot the amplitude spectrum in octave
Created attachment 25464 [details] kst file of the simpler case The attached uses a simple 2*cos(t) function for about 8 cycles to calculate the amplitude spectrum. Kst identifies the single peak in the amplitude spectrum as 2.0
The Kst values look okay.