Talk:Raised-cosine filter

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[edit] Analogue or digital

PAR said on Oli Filth's talk page:

"The raised cosine filter is listed on the linear analog filter template, but it is a linear DIGITAL filter. This should be fixed. PAR 21:29, 25 August 2006 (UTC)"

I wasn't even aware that the "analog filter" template had been added, but according to the history, you added it!!

Don't change the subject! My bungled edits are not the subject of this discussion! Please put all such discussions on the Wikipedia page [[Bungled edits of PAR]] unless that page has been deleted for excessive length. PAR 22:56, 25 August 2006 (UTC)

As to whether raised-cosine is analogue or digital, it's an interesting question. Technically, "raised-cosine filter" as presented in this article is just a mathematical expression that operates in continuous-time, continuous-frequency; this would imply an analogue implementation. However, it happens to be implemented digitally in pretty much all applications. However, the digital implementation requires discrete-time equations. So it's probably best to not call it either. Oli Filth 22:12, 25 August 2006 (UTC)

Perhaps a template for linear digital filters? PAR 22:56, 25 August 2006 (UTC)

Perhaps, however there's currently nothing in the raised-cosine article that even hints at the digital implementation - the equations would be different, as they'd be discrete-time (obviously).

Actually, I'm not sure what specific types of digital filters there are. Because the designer has so much more flexibility in their design than in the analogue domain, generally digital filters are custom-designed according to requirements, using the Parks-McLellan algorithm, etc., or designed and then multiplied by an appropriate window. I'm not sure how many specific digital filters there out there with names. Oli Filth 23:04, 25 August 2006 (UTC)