Howtosignalprocessing
- How do you find frequencies in FFT?
- How do you get to peaks in FFT?
- What do peaks in FFT mean?
- How do you find the spectral peak?
How do you find frequencies in FFT?
Let X = fft(x) . Both x and X have length N . Suppose X has two peaks at n0 and N-n0 . Then the sinusoid frequency is f0 = fs*n0/N Hertz.
How do you get to peaks in FFT?
Look for points where the value for the difference function goes from positive to negative. Those are your peak points. To find the most prominent peaks, compute the second order difference function at the points obtained from the first order difference and select the ones which are of highest magnitude.
What do peaks in FFT mean?
The peaks are the frequencies at which the vibration amplitude is maximal. Here, they appear to be at about 900 Hz, and about 1200-1300 Hz.
How do you find the spectral peak?
For a particular spectral peak, the dichroic ratio R is defined by the relationshipR = A⊥/A∥where A⊥ and A∥ are the absorption of the LB films when the light is polarized perpendicular or parallel to the dipping direction, respectively.
