How to plot fft outputs in frequency domain?

Hi all,

I have attached the m-file for information about my question.

I have time-history acceleration data named BodyAccel_y in the workspace. I converted it to frequency domain by using fft in MATLAB.

However, as I noticed, the outputs are complex numbers.

I would like to plot the output data on Y-axis against their individual frequencies in X-axis.

I am new to this subject. I would appreciate any guidance/suggestion/instruction provided for this matter.

Thank you.

Answer 1

[KSSV]

You read here....https://in.mathworks.com/help/matlab/ref/fft.html

You have to generate the frequency values based on the sampling you have and use abs of the result of fft.

[Chutiphon Moranon]

Thank so much. I have followed the instructions in that link. It is really helpful.

Answer 2

[Arham jain]

if you want to plot the magnitude use

Y = abs(fft(BodyAccel_y));

if you want to plot phase use

Y = angle(fft(BodyAccel_y));

[Chutiphon Moranon]

Thank you so much. Your reply is helpful.