Talk:Roll-off

A fact from Roll-off appeared on Wikipedia's Main Page in the Did you know column on 13 July 2009 (check views). The text of the entry was as follows:

Did you know... that roll-off is an electronic filter parameter of significance for removing muscle activity noise in electrocardiograph machines?

A record of the entry may be seen at Wikipedia:Recent additions/2009/July.

Wikipedia

Electronics Low‑importance

	Electronics portal This article is part of WikiProject Electronics, an attempt to provide a standard approach to writing articles about electronics on Wikipedia. If you would like to participate, you can choose to edit the article attached to this page, or visit the project page, where you can join the project and see a list of open tasks. Leave messages at the project talk pageElectronicsWikipedia:WikiProject ElectronicsTemplate:WikiProject Electronicselectronic articles
Low	This article has been rated as Low-importance on the project's importance scale.

Professional sound production Mid‑importance

	This article is within the scope of WikiProject Professional sound production, a collaborative effort to improve the coverage of sound recording and reproduction on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Professional sound productionWikipedia:WikiProject Professional sound productionTemplate:WikiProject Professional sound productionProfessional sound production articles
Mid	This article has been rated as Mid-importance on the project's importance scale.

Two suggestions

Good job on creating a solid article! I have only a couple of suggestions:

It's probably worth making clear in the article that this concept isn't exclusive to electrical networks; I'm sure it applies to other frequency-dependent systems such as mechanical resonators. It also has meaning in the digital domain.
I'm not sure the distinction between passive and buffered higher-order systems is relevant, as in both cases the pertinent point is that the asymptotic roll-off is the same. And at the moment, the article sort of implies that Butterworth, etc. filters only exist in passive topologies.

Oli Filth^{(talk|contribs)} 11:05, 5 July 2009 (UTC)[reply]

Thank you for the kind words. I have reworded the first sentences in the lede to make it more general. Do you think that is ok now? On your second point, did you write that before I made this edit which was meant to address that very point, I suspect we may have "crossed in the post", or do you think it still needs some work. On the digital issue, a method of synthesising higher roll-offs in the digital domain is mentioned, but you are right the article is skewed to passive analogue, that's my background and I tend to write about what I know. SpinningSpark 11:25, 5 July 2009 (UTC)[reply]

Your rewording largely covers it, although perhaps "LTI system" would be better than "transmission function".

As for higher-order filters, my thought was more that we could merge the two sections into one quite safely, as I believe that the details on buffering and coupling are largely unrelated to asymptotic roll-off. I think all that needs to be something to the effect of "higher-order systems have multiple poles; however in general the roll-off still converges to a constant gradient at high frequencies". Oli Filth^{(talk|contribs)} 12:56, 5 July 2009 (UTC)[reply]

Is this an improvement? SpinningSpark 15:58, 5 July 2009 (UTC)[reply]

Reference missing

The "Mayer et al." reference listed under the Notes section isn't mentioned in References or anywhere else. Which article/book is that? --Yerpo (talk) 13:11, 13 July 2009 (UTC)[reply]

It is there, right at the end: ISBN 089004385X. SpinningSpark 16:28, 16 July 2009 (UTC)[reply]

Circuit error

Concerning following image: Multiple order RC filter buffered between stages The output of the op-amp must feed back to its minus input which is wrongly connected to ground! —Preceding unsigned comment added by 213.102.118.193 (talk) 01:12, 19 December 2009 (UTC)[reply]

It's not an error, and it's not an op amp. The error is that you are assuming that all amplifier symbols are op amps. SpinningSpark 03:46, 19 December 2009 (UTC)[reply]

Attenuation at Corner Frequency for Various Orders

It is worth drawing attention to the definition of corner frequency for higher order filters. For a 12 dB/octave filter, should the attenuation be -6dB at the corner frequency? Yes is the most sensible answer, since an inclination to define the corner frequency as the -3dB point will become rather meaningless for a very high order filter with all of its poles at the same frequency (which will be a long way off the -3dB frequency). — Preceding unsigned comment added by David.J.Greaves (talk • contribs) 14:06, 7 May 2019 (UTC)[reply]