# Talk:Composite image filter

Today I see this image in the article:
The caption claims it is a low-pass filter, but it appears to be a high-pass filter to me.
Is swapping the C and the L all that needs to be done?
--68.0.124.33 (talk) 21:13, 21 August 2008 (UTC)

You are right of course, that is high-pass.  By all means correct the image if you want to.  It would be easier to change the caption though.  This would not change any of the meaning of the article, and high-pass is the most often used section. SpinningSpark 10:11, 23 August 2008 (UTC)

This review is transcluded from Talk:Composite image filter/GA1. The edit link for this section can be used to add comments to the review.
I come to this as an intelligent but ignorant reader, and it is my habit to comment on the article as I read it the first time from printed copy.
I'll thus expand this review over time. It may take a few days to review it fully. I'll make what I consider minor, uncontroversial copy edits, but feel free to revert them. Other suggestions for copy edits I'll list here.
Reviewer: Si Trew (talk) 08:42, 19 July 2010 (UTC)

I've now completed the review except for checking images for licensing. Take as hold. I've marked with a tick ( below where I've had a concern but changed it myself. Si Trew (talk) 10:54, 19 July 2010 (UTC)
GA review (see here for criteria)
It is reasonably well written.
a (prose):  b (MoS): 
 Prose is somewhat technical because of the nature of the subject, and I see no point in this context linking words such as "resistance" and "impedance", but have added a few with which I am not familiar as an erstwhile electronics engineer but not an expert on filters. I would like the nominating editor to check my copy edits in case I have inadvertently changed the meaning.
 Don't see any particular problems with MoS. I note variables were initially in <code> style but later this was not upheld, I put them all in that style (may have missed a few) but not the names of the filters, so "m-type" but m.
I've done some copy editing where I thought backwards ran sentences until reeled my mind, and other minor changes in terminology.

It is factually accurate and verifiable.
a (references):  b (citations to reliable sources):   (OR): 
 AGF on references, I've put them in {{cite book}} and {{cite journal}} templates.
It's difficult to see where some of the hard numbers come from, I've put {{cn}} in a few places. I imagine these will be to the existing references, no problem with that, but I think in some places they should be explicitly called out.
 References have been expanded and improved. Si Trew (talk) 11:25, 4 August 2010 (UTC)

It is broad in its coverage.
a (major aspects):  b (focused): 
Covers the topic well with good internal links, appropriate balance of clarity/simplicity and technical detail, refers to other main articles appropriately.

It follows the neutral point of view policy.
Fair representation without bias: 
A few places say that there are advantages or disadvantages and these need citations, but I fully expect they are covered by the citations, so adding them will I imagine be all that is necessary.
} Looks OK now. Si Trew (talk) 11:25, 4 August 2010 (UTC)

It is stable.
No edit wars, etc.: 
Mostly the work of one editor, but has had good input from others.

It is illustrated by images, where possible and appropriate.
a (images are tagged and non-free images have fair use rationales):  b (appropriate use with suitable captions): 
I've placed (most of) the images in galleries since I think the attempt is to make them line up nicely and be the same size etc, which is what a gallery is for; however other editors might wish to tweak the gallery parameters.
Minor comment: The circuit diagrams use a mix of symbols and fonts (though all are perfectly clear).
Overall:
Pass/Fail: 
Holding for the citation improvements, will happily pass when they're done. Si Trew (talk) 11:09, 19 July 2010 (UTC)
Passing now that Spinningspark has made the changes meeting my concerns. Congratulations and thank you for your hard work. Si Trew (talk) 11:25, 4 August 2010 (UTC)
Unfortunately, I have many problems with the edits you have made to the article.  Even more unfortunate, you have made so many edits that it is now impossible to just undo the parts I don't like: it goes all the way back to your early edits on the lede.  It is going to be simpler to revert to a previous version and then reinstate the acceptable parts.  However, I certainly don't want to be combative about this, so I thought it best to discuss it here first.
You have simplified the lede and I think I see what you are trying to achieve - getting the subject into the first sentence, but what we have there now is just wrong.  "Composite image filters are Electronic filters designed with considerations of image impedance" is not the essence of composite image filters.  The essence is that they are composites of two or more different classes of image filter sections.  Something like that could have been the opening sentence.  I chose not to do that so that it could be first explained to readers who did not know what an image filter was.  "The image impedance point of view" is referring to a definite design method.  If you want to be a bit more formal "image parameter method" could be used but "considerations of image impedance" just does not convey the right meaning.  I don't quite get why you want to change "built up from" to "assembled from".  Again, this does not convey the right meaning.  The filters are built up theoretically from the basic sections, but the final filter is not constructed by simply "bolting together" these cells - there is also a component minimisation process that goes on as well which can end up with a filter that does not contain any of the original sections as an identifiable unit as shown in the example.  I know this article does not cover such ideas, but distributed element filters are currently very much on my mind having just succeeded in getting that article through a very difficult FAC and "assembled" would be even less appropriate for such filters which are printed as one single piece in one go.
It is incorrect to imply that the operational calculus is not a mathematical form.  As originally described by Heaviside, it lacked formal rigour (according to the mathematicians) but is still mathematical.  I also dislike the other sentence you changed in the same edit and will explain why if requested.
I have never been particularly fond of citation templates and they are not mandated - it is editorial choice.  They are certainly not a GA requirement.  Templates are often difficult to persuade to format exactly as one wants and I find it far simpler to format manually in plain text.  This would not be such a problem if the article was more or less complete, but I am being asked to provide additional citations at the same time the citation style has been changed.  I am therefore faced with either dealing with the templates or first reverting en masse.  I suggest that we stick to the principle found in WP:CITE, "Once a style is selected for an article it is inappropriate to change to another, unless there is a reason that goes beyond mere choice of style."
The image method.  Why cut "The"?
L section - don't quite get why you think that link is useful.  L-section is clearly shown on the chart (although the chart has been rolled up by another editor).
Pole of attenuation is not the same thing as a pole of a function on the complex plane.  In fact, a pole of attenuation will correspond to a zero of the complex transfer function.  But that would probably by a bad thing to put in as well, the image method simply does not analyse circuits in terms of complex rational functions as modern circuit analysis would do.  The starting concept of the method is from something fundamentally irrational - the infinite chain.
I know I started it, but I think the proliferation of code tags for variables is bad - it is not following MOS:MATH.  The original reason for the code tags was to get a serifed pi in "Π-section" to match diagrams and get a better looking pi.  Naturally "T-section" was also done for consistency but the practice then wandered into variables where "T" and "Π" were subscripts.  I now think all the variables should be done in a MOS compliant way either with normal html or possibly LaTeX scriptstyle which would also get a serifed font.
SpinningSpark 18:48, 21 July 2010 (UTC)
Hi Spinning.
Yes, it may be better to revert if that is how you feel. I prefer to make small edits that stand on their own feet so that each can be seen for what it is rather than a huge edit where you can't see the meat for the potatoes. I think that is borne out by the fact that you can now enumerate, above, lots of separate changes. In fact you could even have given the differences for each of those changes.
I'll attempt to address your concerns. First let's get to the lead (I don't know why there's this new tendency to call it a "lede"). I would regard myself as intelligent but ignorant about composite image filters. I think it is then common ground that I didn't understand the lead and so changed it to what I thought it meant. If it didn't mean that, or couldn't explain that to someone with an HNC in electronic engineering then I think there is something wrong with the lead. I perfectly accept that I could well have got it wrong; the fact I did shows it is confusing in the first place. We can work together to simplify it while also making sure it is correct.
In the lead, I didn't know (and I suppose still don't know) what an image filter is, in the sense that the "image" here is obviously not a picture. I think the goal here is kinda to say that "image" here is a jargon/technical word for some kind of sample – that's no good of course but  you see what I mean? Image here is some kind of waveform. While it is absolutely OK to refer to other articles about this, in the lead we should try to convey the meaning to an intelligent but ignorant reader, and to my mind such an ignorant reader will take "image" in its everyday sense.
I've not been doing GA review for long, so please excuse me if I am somehow out of order on some technical point of process. I am sure you know that I am doing it in good faith, in fact you said so on reverting my edits on another image filter article. So I am sure we can work together to get this to GA.
"The image method" why cut the? I dunno. That was probably a mistake on my part.
L section. Well it is obvious to you that the graph looks like the letter L. This is not stated in the article, and I couldn't find an article where it's defined like that. In fact the thing is you are discussing L half sections and so well if I cut an L in half at its vertex I get two straight lines. Again, this is a question of using technical terminology without defining it. I happily accept that the particular link was maybe not useful, but we need a definition or link. REmember, not everyone can see the pictures, and even if they can, not all of them will associate a graph that has some particular form with the letter L.
As for MOS:MATH, that's fine if you change those code things all out. I was just trying to make it consistent – I don't mind if they all go.
You're right {{cite}} is not mandated (and I agree, I don't think the MoS should mandate any particular template, as it does come close to at times). The only thing is if you use the template you kinda know it meets MoS, excluding any implementation errors.
With pole of attenuation, I got the links from the other related article (you also the main editor there) and are linked thus. So again if it doesn't say what it means, then what does it mean? You should make that clearer. THe fact that I hunted to find out what pole you were on about and got it wrong might indicate to you that it was not clear in the first place.
It;s hard on balance to decide whether you should  think on balance you should revert it or work from what we have. THat's a tough call and up to you. Certainly, anything I've changed to introduce errors must go. It may be that we decide to fail it and then take it to GAR when someone else can give a second opinion. But it was sitting on the backlog for quite a while and I thought well it deserves a look over and I do have a vague electronics background, so I think I am qualified to review it from that perspective. But it very much depends of course on what you expect your audience to be; if it is for a more specialised audience then I quite happily rule myself out and we can sort that out as part of GAR or whatever.
My sincere thanks for your excellent contributions to Wikipedia and for your assumption of good faith and that you know we can work together to fix this. Si Trew (talk) 20:55, 21 July 2010 (UTC)
Thanks for the response, I think we are on the same wavelength here.  The choice is that either you can try and incorporate my concerns with your edits in the current version or we can revert to my last version and I will start working through your concerns and incorporating them.  I prefer the second option.  I am fully with you that lots can be improved in this article for understandability to the non-specialist, I just need a list (which you have provided) of what is not being understood to work on.  Anyway, it is getting too late here to do any more tonight.  It may be the weekend before I come back to this. SpinningSpark 00:16, 22 July 2010 (UTC)
That's fine, revert it then. When I started doing GA I asked if it was OK to edit articles and was told it was not just accepted but encouraged to do so. However, of course different editors edit in different ways, and if you think it's better to start from where you left off, then that's fine by me and no hurt feelings.
One, I think, uncontroversial change you might want to keep is putting the images into galleries so they all line up nicely. Even there, I was aware that the sizes I'd made the galleries may not be to everyone's taste. Si Trew (talk) 14:21, 22 July 2010 (UTC)
Reviewers editing articles is very much encouraged, and I agree with that.  You should not let my concentration above on the negative put you off from doing so.  And yes, there are some good things in your edits (including the galleries) and I will reinstate them.  It is just unfortunate that you did not make those edits first so they could be excluded from the revert, but that's just the way it goes sometimes. SpinningSpark 18:04, 22 July 2010 (UTC)
I have now addressed all the {{cn}} tags and the math formatting.  Please check that I have not accidentaly lost any of the cite tags in the process of reverting.  On the consistency of images issue, this is partly because they have been provided at different times with different applications, but mostly because another editor has redrawn some of them.  I am willing to make the images a consistent set, but it will be in my style and will necessarily involve reverting another editor.  The style will be as in the Balanced circuit article.  If you want another style, you will need to ask another editor. I think that is everything, please let me know if I have missed anything. SpinningSpark 19:18, 24 July 2010 (UTC)