Talk:Bessel filter

"Bessel filters are often used in audio crossover systems." That is not true. In fact, I've never seen one used that way. Audio crossovers are almost always Butterworth or a combination of two Butterworth filters that make up a Linkwitz-Riley filter. — Preceding unsigned comment added by ~2026-41204-54 (talk) 16:48, 23 July 2026 (UTC)

I am not an expert in filter design applications, but I have worked with a great many filter design application experts. Typically, they have their own way of achieving a working outcome because they are experts, but they frequently do things differently. The key work in the phrase at issue is "often", as opposed to something like, "primarily". The author does seem to have a valid reference or personal skills to justify the use of "often". My background is in the VHF and microwave frequencies, so I have no qualifications to comment on audio crossovers, but perhaps you could augment the article with more information regarding alternative audio crossover designs without straying to for from the core topic of Bessel Filters. Netshine2 (talk) 18:28, 25 July 2026 (UTC)

omega0 is not the cut-off frequency! This got me totally confused while I was trying to implement one. omega0 is a frequency chosen to give you the cut-off frequency you desire, which isn't the same thing. I have added a link to the paper that told me this (although I forgot to log in when I did it. It is http://ece-www.colorado.edu/~ecen2260/slides/FilterSlides.pdf The next question, of course, is how do you calculate omega0? I'll do some more thinking. Tim Band 11:51, 3 December 2007 (UTC)

omega0 is the reciprocal delay. You could work out a formula for 3dB point relative to omega0, I'm sure (it will depend on the order). Dicklyon (talk) 06:24, 27 August 2009 (UTC)

Can anyone explain how to realise a Bessel filter? How do you practically connect your operational amplifier? I really like this Bessel approach instead of the fast filters that are available. —Preceding unsigned comment added by Knoppson (talk • contribs) 22:46, 13 February 2010 (UTC)

Divide it up into second order sections and connect them as biquads — Preceding unsigned comment added by 71.167.69.198 (talk) 01:36, 29 March 2016 (UTC)

The Texas Instruments App Note: Active Low-Pass Filter Design does just that. ~2026-41204-54 (talk) 16:51, 23 July 2026 (UTC)

External links modified

Hello fellow Wikipedians,

I have just added archive links to one external link on Bessel filter. Please take a moment to review my edit. You may add {{cbignore}} after the link to keep me from modifying it, if I keep adding bad data, but formatting bugs should be reported instead. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether, but should be used as a last resort. I made the following changes:

• Attempted to fix sourcing for http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/bes.htm

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 5 June 2024).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—^{cyberbot II}_{Talk to my owner:Online} 07:43, 29 March 2016 (UTC)

Equation Error

Before I created my account, I tried to correct the gain equation in the Example section, but a bot reverted the change in short order. It looks like the equation in the original article was correct, but an editor (173.218.206.57) changed it on 18 July 2020. The coefficient for the omega squared term should be 45, not 15. The gain equation is easy to derive from the transfer function and has nothing to do with, as the editor suggests, substituting omega squared for s. Once the equation is corrected, then an omega value of 1.756 (or 1.75567) yields a gain of sqrt(0.5). — Preceding unsigned comment added by HenriJBass (talk • contribs) 13:07, 13 October 2020 (UTC) Update: I corrected the equation. — Preceding unsigned comment added by HenriJBass (talk • contribs) 17:26, 13 October 2020 (UTC)

Unclear if Bessel filters are always low-pass or can be high-pass/band-pass

The article only shows examples and properties of low-pass Bessel filters, but not high-pass nor band-pass Bessel filters. It is unclear if Bessel filters only work in low-pass mode, or if high-pass and band-pass are also possible, since the article never states either position explicitly; and, in that case, how the group delay behaves. I have been unable to find any examples of Bessel filters that aren't low-pass and show the behavior of the group delay, so I don't know if this is possible at all. Could someone clarify this in the article? --Cousteau (talk) 11:30, 14 March 2025 (UTC)

Bessel filters can always be transformed to high pass, band pass and band stop topologies, but none of those would retain the pass band linear phase characteristic, which would largely defeat the purpose of designing a Bessel filter to begin with, which may be the reason you are unable to find any references on the subject. The distorted linear phase may be mitigated with the use of delay equalizers and/or arithmetically symmetric frequency band pass translations, but those are advanced filter design topics beyond the scope of Bessel filter design. Netshine2 (talk) 17:35, 14 March 2025 (UTC)

Low-pass filters are given as examples throughout the page, but high-pass Bessel filters have the same response trait of maximally flat phase throughput. They have the same basis. I added some text to remind the reader about high-pass filters. Binksternet (talk) 20:50, 25 July 2026 (UTC)