# Fir\_filter\_ccc::filter function confusion

**URL:** <https://www.ruby-forum.com/t/fir-filter-ccc-filter-function-confusion/240749>\
**Category:** GNU Radio\
**Created:** [April 29, 2014, 4:43am UTC](https://www.ruby-forum.com/t/fir-filter-ccc-filter-function-confusion/240749 "2014-04-29T04:43:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [April 29, 2014, 4:43am UTC](https://www.ruby-forum.com/t/fir-filter-ccc-filter-function-confusion/240749/1 "2014-04-29T04:43:05Z")

</div>

Hello,

Hi, I am trying to calculate the conj(w(n))\*s(n) where w(n) is the  
filter weights and s(n) is the signal and Both are complex numbers. I  
wanted to use fir\_filter\_ccc, but I noticed that it uses  
volk\_32fc\_x2\_dot\_prod\_32fc function to calculate the taps.

However, there is another volk function called  
volk\_32fc\_x2\_conjugate\_dot\_prod\_32fc which I presume would be the  
correct function to call.

So is this correct? Should I be using the filter function in  
fir\_filter\_ccc?

Thanks.