NVH

Nancy Jewel Mcdonie

Hi all,

Does anyone know how to convert from time domain (show as figure below) to function: A*sin(w1t) + B*sin(w2t)??

thanks. 

Andrew_21618

Thats very hard to guess the inputs of your problem and what do you desire exactly. But from fundamental point of view, you need to record at least 1024 points, dump them to Matlab or Octave, make an FFT, and analyze the frequency, and amplitude balance. Use that as initial values for 6 parameter optimization with least mean square cost function; 2 for frequencies near the found guess, 2 for amplitudes near the found guess, and 2 for phase shifts (you can try extracting it from the fourier image, but it is less precise and you will finish with fitting in the whole 0~2pi range ).