Signal Processing Stack Exchange
Signal Processing Stack Exchange

Questions tagged [lpc]

44 questions
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2 answers

Gentle request for explanation on LPC and LPCC coefficients :)

If I understand what LPC does, I think. It predicts the next sample by taking into account previous $p$ samples. I don't understand why it is useful in DPS and speech recognition. I also came across LPCC that can be derived from LPC and are related…
Celdor
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3 answers

What is the need for prediction filter in PCM and DPCM?

The DPCM works by the difference between actual samples and predicted samples. If we already have the actual samples, we can quantize it and encode it later. But why we use prediction filter? And by the definition "predicts the present samples…
Venkat Karthik
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4
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2 answers

Matching LPC frequency response to raw sample data frequency response

Background: The intention is feature/formant extraction from speech input. I have used an FFT on raw samples in the past and have done simple peak picking from a weighted average of frequencies over time. That gave results that approximated a voiced…
Firstname_Numbers
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2 answers

How do I go from LPC coefficients to a filter polynomial?

I've recently begun experimenting with LPC, and while I understand that it works, I'm still slightly lost on why it works. Specifically, I understand that LPC involves finding coefficients $a_1, a_2, \ldots a_p$ such that for a signal…
Draconis
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3
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0 answers

Remove the extra peaks by lag

Suppose that we have some peaks of a signal and we know the time lag between dominant peaks. How is it possible to remove the extra peaks by applying time lag ? Lets say it in MATLAB [corr]=xcorr(signal,signal); [val1…
amir ghasemi
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1 answer

Linear Predictive coding vs AR modeling

I'm looking for a suitable explanation of the circumstances in which the LPC error polynomial for a discrete time process x[n] is replaceable with an error polynomial categorized under the AR model? I found this book which states that LPC reduces to…
Abhinav
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2
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1 answer

Linear Prediction task

$$x[n] = \big(A_1 r_1^n\cos(\omega_1 n) + A_2 r_2^n \cos(\omega_2 n) + A_3 \sin(\omega_3*n) \big)u[n],$$ where $\qquad \omega_1 \ne \omega_2 \ne \omega_3, \qquad |r_1|,|r_2|<1 $ I need an linear prediction model that perfectly predicts the signal…
siegfried
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3 answers

Understanding LPC for Formant Estimation

I went through the Matlab tutorial on Formant Estimation using LPC Coefficients. Though I vaguely understand the details, it's not entirely clear why we need to do this. From http://person2.sol.lu.se/SidneyWood/praate/whatform.html: A formant is a…
Sean
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2
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1 answer

Linear prediction (LPC) of Sine wave samples around maximas

I think I missed class when this was explained ... Anyway as part of a bigger project I have to implement a LPC to predict 2-3 future values of a sinusoidal process. I wrote a small Matlab m-file to calculate the predictor coefficients and plot the…
Skaveelicious
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how to detect number of syllables in a batch of audio recordings?

I have a corpus of short speech samples from Kiswahili speakers, and I want to detect the number of syllables in each audio recording. How should I approach this task? Background: I asked a conceptual/programming variant of this question on…
Eric Green
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What is actually transmitted following LPC of a speech frame?

For each frame, what's sent over to the receiver for decoding? The coefficients , pitch in some bits, voiced/unvoiced classification in another bit? Another broad question to develop intuition about LPC and CELP for speech encoding. By using…
panthyon
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2 answers

Improving the separation of a signal into source and filter

I am implementing a voice morphing system, but I am having difficulties getting a good quality output signal. The method I am using is LPC analysis and synthesis. In theory, the LPC process should split the signal into a source/filter representation…
bennji_of_the_overflow
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DFT, cepstrum, LPC for feature extraction

I am a newbie in speech processing and experimenting to get a feel. I have extracted some speech segments using a window function and I want to find distance between a pair of segments. First, I took DFT of a segment and downsampled from the…
Zoran
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Strange result in simple LPC simulation of a sinus

I'm trying to understand how Matlab LPC function works. So I made a little example script : I generate a real cosinus, calculate the LPC coefficients of this signal and then I try to predict the signal using only its first samples of it. clear…
graille
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Zero-padding vs. nonzero-padding in computation of auto-correlation with FFT

Isn't the usual zero-padding in the computation of the auto-correlation function with FFT just one of many possible extrapolations of the original signal? If I have a measured signal which has good reason for having non-vanishing mean (e.g. the…
oliver
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