## Forums Search for: LPC

## pitch synthesis and lpc codebooks and excitation signal

inI am trying to use gsm network to send secure data encoded as voice. For this purpose during my initial research I used 8 bits as lpc codebook...

I am trying to use gsm network to send secure data encoded as voice. For this purpose during my initial research I used 8 bits as lpc codebook index and 4 bits as pitch index. I used these 12 bits to produce 160 samples of voice like data. I am new to dsp so using my limited knowledge I generated random sequences, passed it thru lpc and used these coefficients to generate codebook. I used impul...

## Regarding LPC to LSF conversion

inHi All, I into iLBC codec.I understood the basics that why the LPC coefs are transformed into LSF theortically, but I find it difficult to...

Hi All, I into iLBC codec.I understood the basics that why the LPC coefs are transformed into LSF theortically, but I find it difficult to understand mathematically. Pls help me with the maths associated with it and links if any. Pradeep

## speech to LPC coefficients

inhello can anyone post me a C code for converting the original speech to its LPC coefficients and then to the LSP. Or just tell me the procedure...

hello can anyone post me a C code for converting the original speech to its LPC coefficients and then to the LSP. Or just tell me the procedure to do it ..thanks This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## too many combinations: Transition probability etc.

inHi I am trying to do some statistics, but I don't know how to solve the problem I am working on. I have N speech segments and I perform a...

Hi I am trying to do some statistics, but I don't know how to solve the problem I am working on. I have N speech segments and I perform a 10th order LPC-analysis of each segment and get a 10-dimensional LPC-vector A(j)=[a1(j),a2(j),....a10(j)] for j=1 to N. I then convert all A(j) to B(j)=[c1(j),c2(j),......,c10(j)] where the coefficients of B(j) are the LSF-coefficients correspon...

## gaussian mixture model

i really need help. i'm doing a voice morphing project and is in need of help with the gaussian mixture model method. i know i will need to...

i really need help. i'm doing a voice morphing project and is in need of help with the gaussian mixture model method. i know i will need to process an audio file into lpc datas and then using the lpc format to create a codebook. however, i do not know what comes after that. what am i to do so that i can morph the sound? Really appreciate it if someone can help me out. Really need the hel...

## GMM morphed.

Hi all, can anyone help me with this? If i were to carry out a Gaussian Mixture Modelling on an LPC data, after that using the resultant i...

Hi all, can anyone help me with this? If i were to carry out a Gaussian Mixture Modelling on an LPC data, after that using the resultant i undergo some level of morphing. would i still need to do any reverse GMM on the morphed data in order to get back an LPC format? If yes, can someone roughly show me how it can be done? p/s the GMM approach i used was the EM algorithm

## LPC for Analysis of 2 Speech Signals

inHi All, I am trying to find the best way to analyze 2 speech signals from 2 different speakers and come up with a 'match percentage' as to...

Hi All, I am trying to find the best way to analyze 2 speech signals from 2 different speakers and come up with a 'match percentage' as to how close they were (ie, did the speakers say the same thing). I have been reading that LPC is great for encoding the basic parameters of speech, but most of the articles are related to compression or building of a vocoder. Has anyone had experience ...

## LPC cowfficient freeze

inIn recent past there was a suggestion thrown to me to freeze the LPC coefficient to save computation cycles and the "rational" is...

In recent past there was a suggestion thrown to me to freeze the LPC coefficient to save computation cycles and the "rational" is speech is stationary in nature! The application is a vocoder. I was shocked and still remain shocked but if you guys have an opinion how to deal with this suggestion. If the filter remains constant, can we still find...

## LPC to cepstra conversion

inHi, please help me to understand why we need LPC to cepstra conversion ? how its work(steps) ?

Hi, please help me to understand why we need LPC to cepstra conversion ? how its work(steps) ?

## LPC to cepstra conversion

inHi, please help me to understand why we need LPC to cepstra conversion ? how its work(steps) ?

Hi, please help me to understand why we need LPC to cepstra conversion ? how its work(steps) ?

## LPC coding doubt

inHi I was reading about LPC coding, and I have a doubt. What i read is that the way we find the coeffecients of a filter is by using an energy...

Hi I was reading about LPC coding, and I have a doubt. What i read is that the way we find the coeffecients of a filter is by using an energy eqn, minimize it wrt the coeff, and later find out (by backtracing) if the input function is closer to a white gaussian noise or a periodic impulse train. While I can figure out how this works out in the end, I can't understand why we chose to minim...

## Question about LPC analysis and noise suppression in speech

Hello, I conducted an experiment in MATLAB related to noise suppression. I have a noisy speech segment X=S+N where S is clean speech and N...

Hello, I conducted an experiment in MATLAB related to noise suppression. I have a noisy speech segment X=S+N where S is clean speech and N is noise. I did LPC analysis of a frame of X and obtained an estimate of a noisy excitation (residual) signal u_noisy. I also did LPC analysis of a frame of S and obtained an estimate of a clean excitation signal u_clean. I then filtered u_noi...

## MELPe MOS vs other vocoders

inHi everyone, I read that MELPe won the DoD & NATO competitions against many vocoders such as AMBE, EMBE, STC, FSHC, HSX, SB-LPC, CVSD, CELP...

Hi everyone, I read that MELPe won the DoD & NATO competitions against many vocoders such as AMBE, EMBE, STC, FSHC, HSX, SB-LPC, CVSD, CELP and LPC-10e, so it has to be clearly better than all of them. See for example at: http://www.compandent.com/melpe_faq.htm#Q06 Although MOS is a very comprehensive and expensive subjective test, it seems like marketing people may have been "shaping...

## LPC Question

inIn LPC we estimate a 10th order all pole model of quasi-stationary speech. The predicted speech is...

In LPC we estimate a 10th order all pole model of quasi-stationary speech. The predicted speech is then y(k)=-a1y(k-1)-a2y(k-2)....-a10y(k-n) Is the 'gain' estimated at all ie the variance of the driving noise of the AR model? Also is this really a predictor? It is not a Wiener predictor in the sense there is no additive white noise and it is only predicting one step. Looks more like ...

## Teaching Assistant seeking help.

inDear Sirs I am a teaching assistant at MSU, and have volunteered to create new labs for the ECE Senior Design class. I would like to make the...

Dear Sirs I am a teaching assistant at MSU, and have volunteered to create new labs for the ECE Senior Design class. I would like to make the intial project a real-time LPC encoder/decoder. I would have the students play with the pitch value, so they would learn about LPC and also get excited about DSP. We currently are using the TMS C6711 DSP board from TI. I've searched high and low, and ...

## Speech identyfication...

inHi!!! I have problem with speech identyfication. I use LPC algorithm and extract reflection coeficient (rc). I have this 10 rc and try...

Hi!!! I have problem with speech identyfication. I use LPC algorithm and extract reflection coeficient (rc). I have this 10 rc and try to identify the person using it. The problem is how I can do this with this rc??? I used Euklides distortion measures but I do not know what can I do next with this :( Do You have any ideas how I can classificate and identify the person using rc from LPC ??? ...

## Question regarding LPC Difference equation

inHi, I was going through the Source filter model of speech production given in "Digital Speech" by author Kondoz. The LPC sysnthesis...

Hi, I was going through the Source filter model of speech production given in "Digital Speech" by author Kondoz. The LPC sysnthesis filter looks like : H(z) = G / A(z) where, A(z) = 1 - SUM{a[j]*z^-j} ; j running from 1 to 10 for speech synthesis. If we transform the above equation into sampled time domain, it looks like: s(n) = G*x(n) + SUM{a[j]*s[n-j]} ; j running...

## RLS and LPC comparison

inHi All, I have implemented a 10th order Recursive Least Squares filter on Matlab for speech and am comparing the weights thus obtained with...

Hi All, I have implemented a 10th order Recursive Least Squares filter on Matlab for speech and am comparing the weights thus obtained with the weights using the LPC function. Then I am comparing the speech quality using PESQ MOS values for various speech files. I run my RLS for lambda=1 (forgetting factor) and delta=.02 (regularization factor), which gives the best performance. Al...

## Basic LPC Codec implemetation

inHi Friends, I have implemented a basic LPC coder in matlab using the following blocks. Kindly let me know your comments on some of my...

Hi Friends, I have implemented a basic LPC coder in matlab using the following blocks. Kindly let me know your comments on some of my questions detailed down. I have taken sample .wav file with sampling frequency -8000 frame length =20 ms = 160 samples Overlap = 50% Block length = 240 sampels Overlapping samples of size 240 is copied from the input speech file. I windo...

## decorrelate LPC coefficients. How?

inHello I have a question regarding 10th order LPC-analysis of speech segments. The analysis returns 10 coefficients C1(k),C2(k),....C10(k)...

Hello I have a question regarding 10th order LPC-analysis of speech segments. The analysis returns 10 coefficients C1(k),C2(k),....C10(k) where k is the number of the speech segment which is being analyzed. My question is : Are the coefficients correlated? For example: Is c1(k) correlated with c2(k)?? If so, how do I decorrelate them in real time? I have thought about doing t...