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Discussion Groups | Matlab DSP | Matched filtering in matlab

Technical discussion about Matlab and issues related to Digital Signal Processing.

  

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Matched filtering in matlab - Ishtiaque Ahmed - Feb 1 8:05:28 2008



hello,
  I need to compress a chirp signal using convolution i.e. by Matched filtering in Matlab. 
  *Can anybody write the steps how to do this in Matlab??
  *How can I define an Impulse function and of what kind should it be? What should I do with
this impulse function?
  Thanks.



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Re: Matched filtering in matlab - Jeff Brower - Feb 2 15:25:16 2008

Ishtiaque-

>   I need to compress a chirp signal using convolution i.e. by Matched filtering in
Matlab.
>   *Can anybody write the steps how to do this in Matlab??
>   *How can I define an Impulse function and of what kind should it be? What should I do
with
>    this impulse function?

Just use MATLAB convolution function.  Convolution is filtering, which is what you're trying to
do.  "Matched"
filtering just means to select something very application-specific as the filter.

-Jeff


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Re: Matched filtering in matlab - Jeff Brower - Feb 2 15:25:50 2008

Istiaque-

>   Thanks for ur reply. Let me explain my job little more:
>   I have to define a function for Matched filter in the range between -(Tp/2) to (Tp/2).
>
>   The equation is below-
>   Smf = exp(-d*2*fc*tau - d*K*tau^2);
>   here, tau= -(Tp/2):(Tp/2).
>
>   Then, i have to convolv my one recereived signal (Srx) with the above Smf, i.e.
S=Sr*Smf.
>
>   I have to call the matched_filter function from another .m file.
>
>   That's what i have to do. Hope to hear from you. Thanks.

Please post to the group, not to me.

-Jeff

> Jeff Brower <j...@signalogic.com> wrote:
>   Ishtiaque-
>
>> I need to compress a chirp signal using convolution i.e. by Matched filtering in
Matlab.
>> *Can anybody write the steps how to do this in Matlab??
>> *How can I define an Impulse function and of what kind should it be? What should I do
with
>> this impulse function?
>
> Just use MATLAB convolution function. Convolution is filtering, which is what you're
trying to do. "Matched"
> filtering just means to select something very application-specific as the filter.
>
> -Jeff


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Re: Matched filtering in matlab - Amit Pathania - Feb 4 8:18:49 2008

Istiaque,
   
  I am assuming that you have an .m file like match_filter.m which has the function defined as
   
  function matchedFilterCoefs = match_filter(fc,K, tau,d)
   
  you will call the filter function to generate the coeficients after providing the arguments
to this function. Then you should use either conv or filter function to filter received signal
Srx. The only difference in the usage will be; convolution will give you m+n-1 samples in S
whereas filter will return S equal to Srx. 
   
  You can also write the logic for convolution yourself, its not that hard to follow the
equation.
   
  -Amit Pathania
  
Jeff Brower <j...@signalogic.com> wrote:
          Istiaque-

> Thanks for ur reply. Let me explain my job little more:
> I have to define a function for Matched filter in the range between -(Tp/2) to (Tp/2).
>
> The equation is below-
> Smf = exp(-d*2*fc*tau - d*K*tau^2);
> here, tau= -(Tp/2):(Tp/2).
>
> Then, i have to convolv my one recereived signal (Srx) with the above Smf, i.e. S=Sr*Smf.
>
> I have to call the matched_filter function from another .m file.
>
> That's what i have to do. Hope to hear from you. Thanks.

Please post to the group, not to me.

-Jeff

> Jeff Brower <j...@signalogic.com> wrote:
> Ishtiaque-
>
>> I need to compress a chirp signal using convolution i.e. by Matched filtering in
Matlab.
>> *Can anybody write the steps how to do this in Matlab??
>> *How can I define an Impulse function and of what kind should it be? What should I do
with
>> this impulse function?
>
> Just use MATLAB convolution function. Convolution is filtering, which is what you're
trying to do. "Matched"
> filtering just means to select something very application-specific as the filter.
>
> -Jeff


(You need to be a member of matlab -- send a blank email to matlab-subscribe@yahoogroups.com )