Hi Sarath, The answer to your question depends on several things outside of the FFT itself. First, the accelerometer. You mentioned that it's output goes from 0V to 1.8V. The relationship between the output voltage and the amount of acceleration depends on the range of your specific accelerometer. For example, does 1.8V equal 1.2g or 120g? Does 0V equal -1.2g or -120g? Does 0.9V (mid-point) equal rest (gravity) at 1g? These specifications will allow you to relate the output voltage to a specific acceleration (V/g), and you should be able to find them in the datasheet. Next, the MSP432's ADC. Based on the specifications of the accelerometer, you'll need to adjust the ADC parameters accordingly. If you set up the ADC to measure 0V to 3.3V, this will reduce the resolution of the ADC (compared to 0V to 1.8V), which will affect the results fed to the FFT. Regarding the FFT, the magnitudes across the frequency domain can be correlated back to the amplitudes of the accelerometer signals, assuming everything discussed above has been setup properly. It's easy to describe, but much more work to actually implement. I'd encourage you to take a look at the following resources for more information. Regards, James MSP Customer Applications
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