Hi,
An ADC just converts an analog signal into a digital signal.
You need to read the datasheet about the data format.
To get the spectrum you need:
* a known, fixed, stable sampling rate
* take 2^n samples (where n should be in integer to perform an FFT. E.g. n= 10 for 1024 samples)
* use a windowing function
* perform the FFT
* calculate the absolute (vector length) of the each output bin (real and imag part)
* do the logarithmic calculation for each output value
* do the X-Y plot
For 2^n samples you get 2^(n-1) frequency results.
The frequency step size is linear and is f_sample / 2^
, starting with 0Hz = DC.
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For more detailed informations you need to read basic informations first. (A forum can not replace this).
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There will be software tools that help you do all the (mathematical) functions for you.
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The power can be calculated by performing an RMS calculation over the desired count of samples.
Klaus