[linux-audio-dev] Re: chebychev

Tim Goetze tim at quitte.de
Fri Nov 1 11:52:00 UTC 2002

Steve Harris wrote:

>On Fri, Nov 01, 2002 at 03:13:28 +0100, Tim Goetze wrote:
>> >Blackman-Harris has the best sidelobe rejection, which is probably what we
>> just to make sure we're talking about the same thing:
>I have:

the difference between the two is next to nothing, mostly a DC
offset. i'll use yours for the next FTs. is that 'Harris' as in
'S.W.Harris'? ;)

>Well, I think its best to develop with maximum wuality, then when its
>working, work out how much we can reduce the CPU cost and still have it
>sound good.

agree. though it's always good to keep in mind what is costly
and what is quick when choosing an implementation approach.
>> good god. know an alternative source for calculating the
>> coefficients? Bill?
>I have some text books that will have it in, I can compare that to NR.

after some NR 5-10 reading, it looks to me like harmonic_gen is 
missing the work pcshft() from the book text is performing, yet
its output seems well-scaled.

it just occurred to me that it may be feasible to skip the
coefficient calculation in realtime by simply storing these
instead of harmonic amplitude tables. makes lerping difficult


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