How to reconstruct original signal from fft?

22 次查看（过去 30 天）
Matej Pericic
Matej Pericic 2017-3-4
评论： Matej Pericic 2017-3-4
Hello everyone!!
I have some measurement data (current) from oscilloscope in .csv file format. I need to make fft from that data and reconstruct original signal from dominant frequencies. I've done fft using code
clc;clear all;close all;
data = csvread('F0000CH2.CSV');
t=data(:,4);
x=data(:,5);
plot(t,x)
dft=fft(x);
plot(abs(dft));
How can I read current values for dominant frequencies and is it possible to reconstruct the original oscilloscope signal from only using dominant frequencies? Below is original current and voltage signal from oscilloscope. Thanks for your help. :)

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2017-3-4
After you fft(), you zero the entries with lower magnitudes (absolute value), and then you ifft() to reconstruct.
  3 个评论
显示 1更早的评论
Walter Roberson
Walter Roberson 2017-3-4
... they are the entries you didn't zero out?
If you want to know what frequencies they are, then I suggest you look at the examples in the fft documentation to see how they construct the frequency labels for the graphs.
Matej Pericic
Matej Pericic 2017-3-4
Thank you for you time and answers. I will look at the examples.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Fourier Analysis and Filtering 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by