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missing samples
dave1
post Jun 11 2012, 14:25
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Hi,
I have a question about missing samples, or non-uniform samples. I found out that audio samples can be reconstructed if they are oversampled. My question is can a 20 second oversampled audio file be reconstructed from the first or last 10s of the same recording, or recover a missing audio from what ever that you have. I know that this has something to do with Fourier transform, so, please, can someone explain me how it`s done, or can it be done? I suspect it is possible with simple uniform frequencies, but not with real life audio recordings.
Thanks
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dave1
post Jun 11 2012, 17:25
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http://en.wikipedia.org/wiki/Oversampling
Yes, I meant less than fs/2, and no, I don`t think CDs are oversampled, I just wanted an answer in the more general sense of signal recovery. I searched more on the net for this and found that missing samples recovery is mostly used in signal processing, but it can be used in audio samples too.
Also I found a paper about recovering missing samples from oversampled band-limited signals http://www.ieeta.pt/~pjf/PDF/Ferreira92a.pdf . Besides equations that I can`t understand, there is a statement in it whitch says that a band-limited oversampled signal is completely determined even if an arbitrary finite number of samples is lost. Does this mean that, if we had an ovesampled signal with, for example, 4 times greater number of samples than the number of highest frequency in it, the signal can be restored completely and without losses in the case a fixed number of samples is missing?
I guess I wanted to know this: if we send an audio file thru unreliable network and receive only half the number of samples we had at the beginning (damaged/partial file), can we use the remaining half to restore the whole audio file? It would be impossible to do that if the file is not oversampled. When one half is rejected, there is no way to know how that half looked like. But, the question of how oversampling can help restore missing samples/audio/data still remains.
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