Converting frequency data to time data

Hi Experts,

I have a Force vs Frequency data of 51 points. frequency starting from 39 and ending with 2000Hz

How do I convert it into Force vs Time using matlab and my time domain result should start with 0.

Can anyone please help with this.

Answer 1

[TED MOSBY]

Hi Lokesh,

To convert your Force vs Frequency data into Force vs Time in MATLAB, you can use the inverse Fourier transform as below:

Define the Time Domain: Decide on the time duration you want for your signal. The time vector will depend on your sampling rate. For example, if you want a total time of T seconds and you're sampling at a frequency of Fs Hz, you can create a time vector like this:

Fs = 10000; % Example sampling frequency (10 kHz) 
T = 1; % Total time in seconds 
t = 0:1/Fs:T; % Time vector from 0 to T with sampling interval 

Interpolate Your Frequency Data:

f_interp = linspace(min(f), max(f), length(t)); % Interpolated frequency vector 
F_interp = interp1(f, F, f_interp, 'linear', 'extrap'); % Interpolated force data 

Compute the Inverse Fourier Transform: Use the ifft function to convert the frequency domain data back into the time domain:

F_time = ifft(F_interp); % Inverse Fourier Transform 

Plot the Results:

figure; 
plot(t, real(F_time)); % Plot real part of the signal 
xlabel('Time (s)'); 
ylabel('Force'); 
title('Force vs Time'); 
grid on; 

You should see something like this:

Hope this helps!

Here is the documentation for the “ifft” function of MATLAB:

www.mathworks.com/help/matlab/ref/ifft.html?searchHighlight=ifft&s_tid=srchtitle_support_results_1_ifft