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Questions tagged [lpc]

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0answers
25 views

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 ...
0
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1answer
32 views

AR Modeling: Why residual is white noise?

I was going through AR modeling. The AR model of a covariance stationary process can be expressed as: $$x[n]=\sum\limits_{i=1}^{p} \alpha_i x[n-i] + \epsilon[n]$$ where $p$ is the model order and $...
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0answers
182 views

Linear Predictive Coding example in MATLAB

I have some data that is highly correlated and I wanted to see if I could try and encode it using linear predictive coding (LPC). Here is how I've been understanding the process: Encoding Generate ...
1
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0answers
45 views

Understanding linear predictive coding in MATLAB

I want to test my understanding of linear prediction by running it on some test data in MATLAB. The way I understand it is if I have some data that is correlated, I can encode the signal with linear ...
2
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1answer
174 views

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 ...
1
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2answers
56 views

What is the definition of Linear Predictive Coefficients when the optimal value is not unique?

Linear predictive coefficients of signal y are defined as the best $k$ coefficients $a_i, i = 1, \ldots, k$, that will approximate $y_n$ by $-\sum_{i=1}^k{a_iy_{n-i}}$. (Best approximation is that ...
1
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1answer
52 views

How to prove Line Spectral Pair coefficient properties?

I am trying to understand the definition of LSP coefficients from http://www.dspcsp.com/pdf/lsp.pdf. We take the polynomial $a(x)$ of degree $M$ from the denominator of the LPC system function, and ...
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0answers
51 views

What's the relationship between excitation and LPC residual

While studying LPC, I have found something that boggles my mind. I'm studying from some university texts but pretty much everything I need for explanation is summed up here. I'd like someone explain ...
2
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1answer
154 views

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 ...
0
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1answer
206 views

taking FFT from DCT

There is a speech signal, $y[n]$, in the time-domain. To take it to the frequency-domain, DCT has been got from $y[n]$ (w = dct(y) in MATLAB). After it, I applied ...
1
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1answer
833 views

Why is LPCC and LPC used in speech recognition

I am currently trying to understand why LPCC and LPC is being used in speech recognition and why? LPC as I understand is model similar to source filter model, modelling speech production, and LPC ...
1
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1answer
398 views

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, ...
2
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2answers
799 views

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/...
0
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1answer
848 views

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 ...
0
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1answer
121 views

How to build a simple model for voice-controlled system?

I want to build a speaker independent voice-controlled system. If I ask 10 people to say one unique word(for example"hello"), and record their voice and do LPC(linear predicting coding) upon them, I ...
3
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3answers
5k views

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 ...
4
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2answers
295 views

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 ...
3
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0answers
112 views

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 ...
0
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0answers
269 views

hamming window for LPC

I am working on a library for generating LPC for speech synthesis. I am currently using a hamming window for the spectral analysis which goes in 200ms blocks over the signal, and does the a-to-k ...
0
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2answers
220 views

pre-emphasis with scaling?

I am working on speech synthesis with LPC and I originally implemented a pre-emphasis filter: ...
1
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1answer
590 views

Division by zero in Levinson–Durbin recursion?

I am doing a LPC analysis of a speech signal using the autocorrelation method. To calculate the LPCs I am using the Levinson–Durbin recursion. In my literature the error is initialized with the first ...
2
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0answers
104 views

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 ...
1
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2answers
228 views

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 ...
1
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1answer
135 views

LPC produces unexpected residual

I have written a vocal pitch shifting algorithm which uses LPC to separate the signal into its spectral envelope (predicted by the coefficients) and the pitch information (the residual error). My ...
0
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2answers
211 views

Preprocessing signal before LPC

I have a signal that contains the speaking of three vowels. The signal is contaminated with dc offset and an interference at 60 Hz. I want to perform LPC for the synthesis of the spoken vowels. Do I ...
0
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1answer
381 views

autocorrelation A to K conversion for LPC speech analysis?

I am building an LPC analysis tool for speech synthesis and did the following to generate my a0 through a10: ...
0
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2answers
322 views

pitch extraction for speech

I am building an LPC analysis tool, and am at the point of needing to do pitch period analysis. I was initially interested in using the Gold & Rabiner algorithm for this, and got a hold of a ...
0
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2answers
476 views

Separating excitation from filtering for sound sythesis

From my days at college I rememeber that LPC splits a signal into a series of slowly changing filter coefficents and an audio-rate residual error signal, such that the original signal gets reproduced ...
1
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0answers
56 views

peak-to-peak test between two signal

Suppose that we have different signals (Pulses). I would like to study which signal has deterministic peak-to-peak distant (lag). For example A=[1 0 0 1 0 0 0 1 0 0 1] and B=[1 0 0 1 0 0 1 0 0 1] and ...
1
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0answers
296 views

Definition of LPCC

would you please tell me what does LPCC exactly do?How can we calculate the coefficients of LPCC? I need to know clearly what is it so i can implement it. I dont know if i am asking this question ...
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0answers
256 views

Getting LPC coefficient by HTK

How can i get lpc coefficient by htk? I know that there is a binary code "HCopy" which is ganna help with that... but my question is how can i read a wav file in htk? and i guess i need activeperl to ...
5
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2answers
3k views

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 ...
3
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0answers
330 views

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 ...
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2answers
2k views

What is the “pitch marker” in the LP-PSOLA algorithm?

The LP-PSOLAR algorithm uses a the Linear Prediciton Coding (LPC) to calculate an error vector from a signal. This error vector is used to calculate the pitch markers. What do these pitch markers ...
0
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1answer
905 views

Derivation of Yule-Walker Equation for LPC

I have derived the Yule-Walker equation as shown below. \begin{align} \hat s(n) &= -\sum_{k=1} ^ p a_k s(n-k)\\ e(n) &= s(n) - \hat s(n) = s(n) + \sum_{k=1}^pa_k s(n-k) \end{align} In order ...
0
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1answer
151 views

Format location from LPC magnitude

I am confusing when I find the lpc roots magnitude, f1=0.9313, f2=0.9308, f3=0.91 and f4=0.95 but when I look at LPC envelope the f1 is higher than f4 in term of magnitude in dB. Could anybody explain ...
0
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1answer
447 views

Remove spurious peaks of Hilbert transform

I want to eliminate spurious peaks of Hilbert transform for finding glottal closure in the linear prediction (LP) residual. I have the following 4 steps: Down-sample. Hilbert Transform. Identify ...
1
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0answers
1k views

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 ...
0
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2answers
792 views

Matching an LPC Magnitude Spectrum to FFT Magnitude Spectrum

I'm trying to get an LPC magnitude spectrum to match to an FFT magnitude spectrum. Basically I want the peak height in the LPC Spectrum to match the peak height in the FFT Spectrum. Thanks to ...