How to recover the original signal using ifft

Question

Enzo Lopes 2024-5-11

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2117706-how-to-recover-the-original-signal-using-ifft

回答： Hassaan 2024-5-11

Hello everyone,

I've written a code to test the ifft function in MATLAB. However, I've noticed that ifft returns the same number of points as fft. I'm aiming to recover the original signal, which had 1000 points along with the time vector, t. How can I achieve this?

Thanks in advance for your help!

clear;clc;close all;
dt=2.5e-9;
f = 10e6;
Nfft=8*4096;
t = (0:1000-1)*dt;
sinal = sin(2*pi*f*t);
figure(1)
plot(t,sinal)
%Cálculo da fft
fftsinal=fft(sinal,Nfft);
%Transformada inversa de Fourier
sinal_recuperado = real(ifft(fftsinal,Nfft));
figure(2)
plot(1:Nfft,sinal_recuperado); 

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Paul 2024-5-11

Hi Enzo,

For this problem, why zero-pad the FFT to Nfft points?

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Answer 1

Hassaan 2024-5-11

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2117706-how-to-recover-the-original-signal-using-ifft#answer_1455986

在 MATLAB Online 中打开

clear; clc; close all;

% Time step

dt = 2.5e-9;

% Frequency of the sine wave

f = 10e6;

% Number of points in the original signal

N = 1000;

% Time vector

t = (0:N-1) * dt;

% Original signal

sinal = sin(2*pi*f*t);

% Plot the original signal

figure(1)

plot(t, sinal)

title('Original Signal')

xlabel('Time (s)')

ylabel('Amplitude')

% Compute the FFT of the original signal

fftsinal = fft(sinal);

% Compute the IFFT to recover the signal

sinal_recuperado = real(ifft(fftsinal));

% Plot the recovered signal

figure(2)

plot(t, sinal_recuperado)

title('Recovered Signal')

xlabel('Time (s)')

ylabel('Amplitude')

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