Regarding Linear prediction analysis.

Hi,

I am working on the linear prediction analysis implementation,I have one
question which is regrding windowing which is done before
LCP, where we have a frame of size 240 samples i.e 40 samples from past,
80 samples of present frame and 40 samples from future. I am using the
linear prediction analysis for decorrelation of signal after acoustic
echo cancellation. I can store the 40 samples from past but how can I get
the future 40 samples from acoustic echo cancellation module. Can you
please tell me how to construct a frame for LP analysis. Thanks in
advance.

Regards,
Neelufar

neelufar.2005 wrote:

> Hi,
> 
> I am working on the linear prediction analysis implementation,I have one
> question which is regrding windowing which is done before
> LCP, where we have a frame of size 240 samples i.e 40 samples from past,
> 80 samples of present frame and 40 samples from future. I am using the
> linear prediction analysis for decorrelation of signal after acoustic
> echo cancellation. I can store the 40 samples from past but how can I get
> the future 40 samples from acoustic echo cancellation module. Can you
> please tell me how to construct a frame for LP analysis. Thanks in
> advance.
> 

It seems like you ripped off the LPC code from some audio codec. You can 
borrow the frame structure from there also. However before you do that 
you'd better get an idea of what exactly are you trying to accomplish 
and why do you need the lookahead processing.



Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

>
>
>neelufar.2005 wrote:
>
>> Hi,
>> 
>> I am working on the linear prediction analysis implementation,I have
one
>> question which is regrding windowing which is done before
>> LCP, where we have a frame of size 240 samples i.e 40 samples from
past,
>> 80 samples of present frame and 40 samples from future. I am using the
>> linear prediction analysis for decorrelation of signal after acoustic
>> echo cancellation. I can store the 40 samples from past but how can I
get
>> the future 40 samples from acoustic echo cancellation module. Can you
>> please tell me how to construct a frame for LP analysis. Thanks in
>> advance.
>> 
>
>It seems like you ripped off the LPC code from some audio codec. You can

>borrow the frame structure from there also. However before you do that 
>you'd better get an idea of what exactly are you trying to accomplish 
>and why do you need the lookahead processing.
>
>
>
>Vladimir Vassilevsky
>DSP and Mixed Signal Design Consultant
>http://www.abvolt.com

Hi,

Sir,I have not ripped off the LPC code from any audio codec. I explored
web to get the details about the LPC, which I am using to convert a sinal
into noise. I want the residual signal of LPC analysis. I went through
some documents and could get the details about the LPC but I have not
found any details about why this look ahead processing is required. Can u
please help me to understand this look ahead process. Need argent help
regarding this.

Regards,
Neelufar.
>

"neelufar.2005" <neelufar.2005@gmail.com> wrote in message
news:ToOdndQQsa8fTWDbnZ2dnUVZ_v6rnZ2d@giganews.com...
> >
> >
> >neelufar.2005 wrote:
> >
> >> Hi,
> >>
> >> I am working on the linear prediction analysis implementation,I have
> one
> >> question which is regrding windowing which is done before
> >> LCP, where we have a frame of size 240 samples i.e 40 samples from
> past,
> >> 80 samples of present frame and 40 samples from future. I am using the
> >> linear prediction analysis for decorrelation of signal after acoustic
> >> echo cancellation. I can store the 40 samples from past but how can I
> get
> >> the future 40 samples from acoustic echo cancellation module. Can you
> >> please tell me how to construct a frame for LP analysis. Thanks in
> >> advance.
> >>
> >
> >It seems like you ripped off the LPC code from some audio codec. You can
>
> >borrow the frame structure from there also. However before you do that
> >you'd better get an idea of what exactly are you trying to accomplish
> >and why do you need the lookahead processing.
> >
>
> Sir,I have not ripped off the LPC code from any audio codec. I explored
> web to get the details about the LPC, which I am using to convert a sinal
> into noise. I want the residual signal of LPC analysis. I went through
> some documents and could get the details about the LPC but I have not
> found any details about why this look ahead processing is required. Can u
> please help me to understand this look ahead process. Need argent help
> regarding this.

1. If you want the things to be done hard and fast, this is business. The
contact is at my website.

2. The windowing is used with LPC for the same reason the windowing is used
with FFT: reducing the spectral leakage. What kind of windowing (if any) do
you need depends on what is your goal.

3. The lookahead is accomplished by delaying the signal.

Vladimir Vassilevsky
DSP and Mixed Signal Consultant
www.abvolt.com