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accelerate-frameworkvdsp

Frequency Range from FFT using vDSP

I have an array of values as input which can be plotted as follows…

enter image description here

Using vDSP_zvmagsD I get an array that I can plot as follows…

enter image description here

How do I get the frequency range that I need to label the x-axis?

Solution

  • The size of your frequency bins depend on the sampling rate of your input signal and the size of your FFT window:

    input frequency / input samples = hz/frequency bin

    Here you can find a more detailed answer by electronics stackexchange user Mark. There you will also find useful information about the tradeof between frequency resolution (bin size) and temporal resolution (when does which frequency occur)