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Observer
Observer
5,132 Views
Registered: ‎10-08-2009

FIR Complier

 

I am using the FIR Compiler and I have a couple of set of coefficients, but I want a bypass mode, I want to load coefficients so that my response is as flat as possible. When I load 142taps_fir_coeficients_unit.coe the filter doesn't work. I get nothing. Yet when I load at the frequency response in the GUI it looks mostly flat. The filter is symmetric so I can't just have one tap. My questions are:

 

Can I have both a symmetric coefficients and non symmetric coefficients? Is the symmetric version a subset of the non-symmetric one, meaning the non-symmetric one is better becaue I have symmetric and non symmetric coefficients or do I have to have one or the other?

 

Why isn't my flat response coeffients giving any output? I am loading both exactly the same way.

 

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Xilinx Employee
Xilinx Employee
5,123 Views
Registered: ‎08-02-2011

Yes, you can load both symmetric and non-symmetric coefficients into the filter. If this is the case, the core will build a non-symmetric structure which just means it won't use the preadder to fold the filter in half when symmetric. Both will still work fine.

 

What does "the filter doesn't work" mean? Zero output? Noise? Wrong response?

 

You should start by sending in an impulse and see if the coefs match the expected set that you've loaded.

www.xilinx.com
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Voyager
Voyager
4,994 Views
Registered: ‎04-21-2014

Exactly right, of course.

 


@bwiec wrote:

Yes, you can load both symmetric and non-symmetric coefficients into the filter. If this is the case, the core will build a non-symmetric structure which just means it won't use the preadder to fold the filter in half when symmetric. Both will still work fine.

 

What does "the filter doesn't work" mean? Zero output? Noise? Wrong response?

 

You should start by sending in an impulse and see if the coefs match the expected set that you've loaded.


 

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