DFT - zero padding avoids aliasing?

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In summary, the conversation discusses the idea of finding the DFT (discrete Fourier transform) of a signal and how zero padding the time signal can affect the resulting frequency points. This can potentially decrease the chances of aliasing. However, it is important to note that this results in a different signal with a different DFT.
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LM741
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hey guys - i can't seem to find find this statement anywhere - but it makes sense to me - could someone please verify.
When you find the DFT of a signal say: x[0]=2, x[1]=4, x[2]=6, x[3]=8 - you will get four discrete points in frequency (per period) now if you zero pad the time signal such that you get x[0]=2, x[1]=4, x[2]=6, x[3]=8 x[4]=0, x[5]=0, x[6]=0, x[7]=0 - you will once agin get four discrete frequency points but now the gap between each period will be larger (thus decreasing any chances of aliasing)


thnks
 
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Sure, but that is a completely different signal with a different DFT. It is an apples/oranges comparison.
 

FAQ: DFT - zero padding avoids aliasing?

What is DFT?

DFT stands for Discrete Fourier Transform, which is a mathematical technique used to convert a signal from its original domain (often time or space) to a representation in the frequency domain.

What is zero padding?

Zero padding is a technique used in DFT to extend the length of a signal by adding zeros to the end. This allows for a finer resolution in the frequency domain, as well as avoiding certain artifacts such as spectral leakage.

What is aliasing?

Aliasing is a phenomenon in which a signal is distorted or misrepresented due to inadequate sampling or processing. In the context of DFT, aliasing can occur when the sampling rate is too low, resulting in overlapping frequency components and loss of information.

How does zero padding help avoid aliasing in DFT?

Zero padding increases the number of samples in a signal, which in turn increases the effective sampling rate. This prevents aliasing by ensuring that there is enough information to accurately represent the signal in the frequency domain without overlapping components.

Are there any drawbacks to using zero padding in DFT?

While zero padding can improve the resolution and accuracy of DFT, it also increases the computational complexity and may introduce some artificial frequencies in the frequency domain. Additionally, zero padding does not completely eliminate aliasing, it only reduces its likelihood.

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