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Windowing problem before LPC
hyeewang
post Mar 17 2010, 02:55
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Why window the signal before computing LPC coefficients?

What is the whys of windowing? I know windowing can prevent spectrum leakage,but LPC is none of business of FFT, so it has no spectrum leakage.

Any comments would be appreciated!
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igor_b
post Apr 4 2010, 03:13
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QUOTE (hyeewang @ Mar 17 2010, 02:55) *
Why window the signal before computing LPC coefficients?

What is the whys of windowing? I know windowing can prevent spectrum leakage,but LPC is none of business of FFT, so it has no spectrum leakage.

Any comments would be appreciated!


in LPC (linear prediction) you are predicting a value of next sample based on some number of previous samples. if you just take a block of signal "without windowing" (apply a rectangular window on a signal to be correct) then, on a beggining of a block you are actually trying to predict something from a bunch of previous zeros, and at the end of a block you are trying to predict zeros from some signal. that is why the prediction error is very high on the beggining and at the end of a block. by using windowing you make this error much smaller.

This post has been edited by igor_b: Apr 4 2010, 03:14
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