On Wed, May 2, 2012 at 2:55 PM, Marcus D. Leech <[email protected]> wrote:

> I have been in the habit of using complex-bandpass filters even when I'm
> just looking for a symmetric response.  I did some measurements
>  today and found a 40-45% performance advantage to using a low-pass real
> filter when a symmetric response is desired.  What's the "crux"
>  of the performance difference?
>
> Needless to say, I ran around and changed all my recent "stuff" to use
> low-pass filters :-)


Complex * complex multiplies are more computationally expensive than
complex * real. For edification and titillation you can read the
volk_32fc_x2_multiply_32fc source. There's an Orc version too which is
easier to read. The moral of the story is you should probably avoid complex
coefficients unless you know you need them.

--n


>
>
> --
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
>
>
>
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