Talk:Negative feedback

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Suppression of sourcing[edit]

From this version of the sub-section on negative feedback amplifiers several notes were removed by Binksternet and then again by Dicklyon. The reason for removing these notes, according to Binksternet is:

this kind of argument inside references is best saved for the main article about the sub-topic

and Dicklyon's reversion is based upon the suggestion:

Please re-do it with nothing in ref tags except references.

Now, what exactly is in these notes that constitutes "an argument inside references" and why on earth should notes be restricted to citations only, without amplification of points raised? That restriction is not normal practice in books and articles. In any event, one of the removed notes is Dunn:

Peter Carroll Dunn (2000). Gateways into Electronics. John Wiley & Sons. p. 192. ISBN 9780471254485. Feedback circuits are mostly bilateral [...making...] feedback models at least awkward 

which simply supports the assertions of the already included reference by Chen. Another of the removed sources is Gray and Meyer, the definitive text on this subject, cited to support the deleted remark that the more general methods are often easier to use:

Paul R Gray, Paul J Hurst, Stephen H Lewis, Robert G Meyer (2001). "§8.8 Feedback circuit analysis using return ratio". Analysis and design of analog integrated circuits (PDF) (4th ed.). John Wiley & Sons. p. 599. This alternative analysis, which is often easier than two-port analysis, is called return-ratio analysis. 

These notes obviously involve no "argument" and are simply supplementary references to support the text. They contain quotes from the sources included simply for the benefit of those trying to find the relevant remarks made by these authors, and they say nothing at all that the WP text has not already said.

The third source removed is the well-regarded text by Jaeger:

Richard C Jaeger, Travis N Blalock (2004). "§18.7: Common errors in applying two-port feedback theory". Microelectronic circuit design (2nd ed.). McGraw=Hill Higher Education. pp. 1409 ff. ISBN 0072320990. Great care must be exercised in applying two-port theory to ensure that the amplifier feedback networks can actually be represented as two-ports 

which is more technical than the text in its introduction of the idea of two-port analysis, although the reader who looks at this source will soon discover this is the traditional approach to the treatment of the unilateral block decomposition of the negative feedback amplifier. Jaeger is worth referencing because he points out very clearly the misleading nature of the unilateral block approach, which is the source of "common errors". (See also Hurst.) The reason for making this a note is, of course, to avoid interruption of the flow of the main WP text, which is the commonly accepted purpose for footnotes.

Removal of these three sources is contrary to one primary purpose of WP, namely to serve as a guide for readers to pertinent literature on a topic. Brews ohare (talk) 14:25, 18 December 2014 (UTC)

It's unclear why you think bloating up this tangent with more sources helps the article. Or why you'd introduce the topic of two-port networks in a footnote just to shoot it down. Dicklyon (talk) 16:37, 18 December 2014 (UTC)
Dick: I'm unclear why providing sources fits into the category of "bloating" or why indicating deficiencies in the primarily pedagogical unilateral block model used in the article is a "tangent". Perhaps you could address these two claims in more detail?
The topic of two-ports is incidental to the point being made, namely that the unilateral block approach lends itself to errors, some a bit subtle. That point supplements what is noted, that this approach is defective.
You have a desirable goal in keeping WP brief, but that can conflict with the goal of an accurate and adequate portrayal. Brews ohare (talk) 17:06, 18 December 2014 (UTC)
I believe you're confused. A two-port is not a unilateral model. The cited comparison involving that is somewhat off topic, comparing different ways to handle the more general case than can be described with traditional feedback concepts. We already have enough acknoledgement of the limitations, and links to more general techniques, so the extra stuff just looks like your usual bloating. Dicklyon (talk) 22:48, 18 December 2014 (UTC)

────────────────────────────────────────────────────────────────────────────────────────────────────Once again the reasonable directives given at WP:SUMMARY are being ignored by Brews ohare. Let's not make this article the place to prove or disprove pet theories. The individual articles are the place for further detail. Binksternet (talk) 23:20, 18 December 2014 (UTC)

Dick: You're right that the general two-port can be bilateral. So the larger issue is that dividing the amplifier into a forward and a feedback block is inadequate, even though it is more general than when the blocks are made unilateral.
Binksternet: Of course it is true that breaking up articles into main articles and subsidiary articles can be a good thing. But then of course the main article should put the subsidiary articles in context, and in particular should give the reader of the main article enough guidance so they know that they would be well served by looking at the other articles. Removing a few citations hardly falls under WP:SUMMARY. Brews ohare (talk) 00:38, 19 December 2014 (UTC)
It is really insulting to have my inclusion of sources labeled by Binksternet as a personal "pet theory". Why are you choosing to be confrontational over a noncontroversial matter found in dozens of sources?
And Dick, the point you bring up that the unilateral block approach is inapplicable even when generalized to a two-block two-port break up suggests that this paragraph on limitations should be expanded to point out this more serious issue documented by Gray & Meyer and by Jaeger & Blalock. Brews ohare (talk) 03:15, 19 December 2014 (UTC)

Proposed final paragraph[edit]

The last paragraph of the subsection on the negative feedback amplifier reads:

Although the diagram illustrates the principles of the negative feedback amplifier, modeling a real amplifier as a unilateral forward amplification block and a unilateral feedback block is sometimes inadequate in practice.1 Methods of analysis that do not make these idealizations have been developed,2 and they are often easier to use.3 For details the interested reader can consult the articles Return ratio and Asymptotic gain model.
Notes
1 Wai-Kai Chen (2005). "Chapter 13: General feedback theory". Circuit Analysis and Feedback Amplifier Theory. CRC Press. p. 13–1. ISBN 9781420037272. [In a practical amplifier] the forward path may not be strictly unilateral, the feedback path is usually bilateral, and the input and output coupling networks are often complicated. 
2 For an introduction, see Rahul Sarpeshkar (2010). "Chapter 10: Return ratio analysis". Ultra Low Power Bioelectronics: Fundamentals, Biomedical Applications, and Bio-Inspired Systems. Cambridge University Press. pp. 240 ff. ISBN 9781139485234. . The Rosenstark and Choma methods are described in Gaetano Palumbo, Salvatore Pennisi (2002). "§3.3 The Rosenstark Method and §3.4 The Choma Method". Feedback Amplifiers: Theory and Design. Springer Science & Business Media. pp. 69 ff. ISBN 9780792376439. .
3 Paul R Gray, Paul J Hurst, Stephen H Lewis, Robert G Meyer (2001). "§8.8 Feedback circuit analysis using return ratio". Analysis and design of analog integrated circuits (PDF) (4th ed.). John Wiley & Sons. p. 599. This alternative analysis, which is often easier than two-port analysis, is called return-ratio analysis. 

This paragraph seems to suggest that the difficulty with the idealized model is entirely due to the forward and feedback blocks being unilateral. However, the problem is more than that because, as pointed out by Dicklyon, the problem remains even if the blocks are made bilateral by representing them as two-ports. This issue is documented by Gray & Meyer and by Jaeger & Blalock. The addition of a sentence to this effect provides a clearer statement of the issues with the simple block representation of the negative feedback amplifier. A possible replacement for this last paragraph is the following:

Although the diagram illustrates the principles of the negative feedback amplifier, modeling a real amplifier as a unilateral forward amplification block and a unilateral feedback block is sometimes inadequate in practice.1 In fact, the issue is not just the unilateral nature of the blocks, and breaking up the amplifier into forward and feedback blocks using bilateral two-port networks also is restricted in practice.2 Methods of analysis that do not make these idealizations have been developed,3 and they are often easier to use.4 For details the interested reader can consult the articles Return ratio, Asymptotic gain model, and Extra element theorem.
Notes
1 Wai-Kai Chen (2005). "Chapter 13: General feedback theory". Circuit Analysis and Feedback Amplifier Theory. CRC Press. p. 13–1. ISBN 9781420037272. [In a practical amplifier] the forward path may not be strictly unilateral, the feedback path is usually bilateral, and the input and output coupling networks are often complicated. 
2Richard C Jaeger, Travis N Blalock (2004). "§18.7: Common errors in applying two-port feedback theory". Microelectronic circuit design (2nd ed.). McGraw=Hill Higher Education. pp. 1409 ff. ISBN 0072320990. Great care must be exercised in applying two-port theory to ensure that the amplifier feedback networks can actually be represented as two-ports 
3 For an introduction, see Rahul Sarpeshkar (2010). "Chapter 10: Return ratio analysis". Ultra Low Power Bioelectronics: Fundamentals, Biomedical Applications, and Bio-Inspired Systems. Cambridge University Press. pp. 240 ff. ISBN 9781139485234. . The Rosenstark and Choma methods are described in Gaetano Palumbo, Salvatore Pennisi (2002). "§3.3 The Rosenstark Method and §3.4 The Choma Method". Feedback Amplifiers: Theory and Design. Springer Science & Business Media. pp. 69 ff. ISBN 9780792376439. 
4 Paul R Gray, Paul J Hurst, Stephen H Lewis, Robert G Meyer (2001). "§8.8 Feedback circuit analysis using return ratio". Analysis and design of analog integrated circuits (PDF) (4th ed.). John Wiley & Sons. p. 599. This alternative analysis, which is often easier than two-port analysis, is called return-ratio analysis. 

I believe this added sentence and source makes the situation clear and leads the reader to sources that explain the matter carefully. Brews ohare (talk) 15:13, 19 December 2014 (UTC)

I would be interested in knowing what this means: "In fact, the issue is not just the unilateral nature of the blocks, and breaking up the amplifier into forward and feedback blocks using bilateral two-port networks also is restricted in practice." What does "the issue" refer to? What does the source say about this other than "Great care must be exercised in applying two-port theory to ensure that the amplifier feedback networks can actually be represented as two-ports", which sounds like a tautology? What does this matter here? I think it doesn't. Dicklyon (talk) 19:01, 19 December 2014 (UTC)
Dick: "The issue" is the adequacy of the representation of the negative feedback amplifier in the provided diagram as two unilateral blocks. Jaeger, as also is the case with every text I know, discusses at length the representation of the negative feedback amplifier using a more general representation as two bilateral blocks: a two-port network for the forward amplifier block and another two-port for the feedback network. I imagine you are familiar with these discussions. Jaeger then points out in the referenced section that in some very mundane examples the port conditions are not satisfied, so what appears topologically to be a two-port is not electrically a two port. If the erroneous assumption that one has a two port is used, incorrect assessments will result for effect of feedback upon the amplifier. The admonition is not a tautology but a word of warning that this error is easy to make. That is one reason the return-ratio approach is better. Why does this matter here? First, it matters that the diagram forming the basis of the discussion is an oversimplified case. Second, as is often said, one reason is that it uses unilateral blocks. Third, as Jaeger points out, even if these blocks are not unilateral, but bilateral (as often is suggested as a cure), the diagram still is a simplified case. Fourth, better approaches (return-ratio, for instance) are available, and of practical importance. The addition of one sentence with a reputable source is hardly a digression adding "bloat" to this short paragraph. Brews ohare (talk) 20:37, 19 December 2014 (UTC)
I'm not sure I agree that the different sources you cite are about that issue. One is talking how two ports might not be the easiest way. The other is saying they may not be adequate, but you haven't told us enough of what it says to give a clue why. I suspect it's about nonlinearity, which is a whole different issue. Anyway, I don't find your added text adds anything useful. Dicklyon (talk) 02:06, 20 December 2014 (UTC)
Dick: I gather that assuming everything I have said is 100% what the sources say, you still opine that the added sentence contributes nothing. If you can explain that point, I'll delve into your uncertainty about whether I can read. The logic is as follows:
1. The diagram is an idealization that does not apply to many practical cases (Chen)
2. One idealization in the diagram is the use of unilateral blocks, which ignores the bilateral nature of many feedback networks. (Chen)
3. A different idealization that uses bilateral blocks also does not apply to some common examples. In other words, the unilateral issue commonly identified as the problem is not the whole story behind the inadequacy of the diagram. (Jaeger)
4. More general approaches are needed, and they exist, that don't use the two-block division. (Sarpeshkar, Gray and Meyer, Palumbo & Pennesi)
Item 3 is what has been added. The rest is there already. Now, item 3 does add to the picture, pointing out that the unilateral issue isn't the point; it is the indivisibility: splitting a feedback amplifier up into a forward two-port and a feedback two-port (bilateral or unilateral) is not always feasible, failing even for some simple examples. This problem exists even for entirely linear (e.g. small-signal) circuit elements. If you continue to doubt that even after looking at these sources and perhaps the WP article discussion here, please elaborate. I will dig up even more sources that will add to your reading to-do list. Brews ohare (talk) 03:01, 20 December 2014 (UTC)
That's just great, taking your argument into main article space. At least it's not as much a disgression there, though it still looks like bloat for the purpose of conversation and argument more than to help the reader. Dicklyon (talk) 20:32, 20 December 2014 (UTC)
I believe you still haven't told us what Jaeger says that implies sometimes a two-port analysis will not work. The quote just says one must be careful to not make mistakes. Dicklyon (talk) 20:37, 20 December 2014 (UTC)
I'll outline what Jaeger does, but the same point is made in all the sources above:
"Many popular textbooks incorrectly apply the feedback theory to these amplifiers because a simple relationship seems to relate the output current to the feedback current. The best way to illustrate the problem is through an example that produces erroneous results."
He then discusses a series-series amplifier and a shunt-series amplifier, in both of which an apparently natural choice for the feedback two-port leads to wrong results. He is forced to use a full-blown mesh analysis to get the right answers, and then verifies the mesh analysis by computer simulation. He traces the error with the two two-port analysis to the fact that the feedback two-ports in both examples are not two-ports despite having two input and two output leads.
Now, he hasn't proved impossibility, but only a trap. He also has shown that to set up a two two-port version in both thee examples is, as Choma says, daunting, if not impossible.
It is perfectly clear that the consensus among authors is that in such cases where the two two-port approach proves intractable, to duck the complexity of a mesh analysis the expedient approach is to use the Rosenstock or the Choma methods. One cannot prove definitively that a given circuit falls into the "impossible" category, but when faced with a recalcitrant circuit that might actually be impossible, the best approach is not to spend an inordinate amount of time beating one's head on the wall, but to use other methods.
The added sentence that you have removed does not make exaggerated claims; all it says is:
" In fact, the issue is not just the unilateral nature of the blocks, and breaking up the amplifier into forward and feedback blocks using bilateral two-port networks also is restricted in practice.Jaeger
The point is that the diagram is not generally useful and its lack of utility is not due to the unilateral choice of blocks, but is more fundamental: some negative feedback amplifiers cannot be fit into this picture, or at least have defied all attempts so far to do so. What is your objection? Brews ohare (talk) 03:43, 21 December 2014 (UTC)
My objection is that you keep making up weird conclusions, like that last one. We already acknowledge, don't we, that other methods are sometimes needed, and we link to them, right? I still don't see the sources concluding that the two-port method is impossible, which is what you seem to be concluding. No need to get into that question here, as the point is too subtle for the audience of this article. You can get into details in Negative feedback amplifier. Dicklyon (talk) 04:14, 21 December 2014 (UTC)
Dick: The reverted sentence says nothing about impossibility. It says the issue of unilateral blocks isn't the only objection, because division into bilateral two ports also has problems. Brews ohare (talk) 04:35, 21 December 2014 (UTC)
I disagree with that conclusion. But the article already has references to the other methods, so why push an intermediate marginal conclusion into it? Dicklyon (talk) 04:39, 21 December 2014 (UTC)
I doubt that you disagree that the diagram is inadequate to describe all negative feedback amplifiers. It is hard to see why the reader would not ask: Well what's the matter? Your answer is: "Don't worry about it - there are other ways to do it." A more complete answer is: "One issue is the use of unilateral blocks that can't describe real circuits, Although the diagram works better with bilateral blocks like two-ports, that approach proves complicated and sometimes fails too. Often other methods that don't use such diagrams prove less frustrating and less liable to error."
Dick, the more complete answer you reverted takes only one short added sentence and provides a source that could be helpful for a reader wondering about what is wrong here. Could it be that your interest in having your way is taking precedence over helping the reader? Brews ohare (talk) 05:32, 21 December 2014 (UTC)

I quit[edit]

OK, having heard the explanation, and the accusation of bad faith, I'm just going to withdraw and let Brews work it out with the other editors. If they are convinced by now with all the explanation, I won't interfere. Dicklyon (talk) 05:44, 21 December 2014 (UTC)

Dick: Refusing any direct response to the issues raised, what choice do you have? Brews ohare (talk) 06:19, 21 December 2014 (UTC)

You have chosen to phrase the issue as some never-proposed thesis that it is impossible to model a negative feedback amplifier as two blocks, when what is said is that such a depiction is subject to caveats, and states the caveats with a source. It is an old trick where the goal is to win a debate and not to further understanding, to set up a strawman position and knock it down, avoiding engagement. Brews ohare (talk) 16:38, 21 December 2014 (UTC)

Brews ohare, you method is to wear down the opposition with continual pointless arguments, another old trick. You are ignoring the bigger picture which is the reader. The additions you wish to make are not helping the reader understand the topic. Keep it simple here. Put extra detail on the sub-article pages. Binksternet (talk) 16:58, 21 December 2014 (UTC)
Binksternet: It is interesting that you think I am engaged in "wearing down" Dicklyon. That view possibly extends from observing the length of this exchange without regard for its content. The basic point is the addition (or not) of a single sourced sentence to the text. Dicklyon's opposition is that it says nothing useful because the existence of other methods has been mentioned. Your view is not that it says nothing, but that it is too much detail in a general article.
Neither of you attempt to support these opposite opinions of yours that are nothing more than a personal bias toward brevity, even at the cost of clarity. A more useful discussion would focus on how to better inform a reader about how to find a more complete idea of the limitations of the diagram that is the basis for the WP description. What is wearing is unending unsupported repetition of personal taste without concern for informing the reader. Brews ohare (talk) 17:54, 21 December 2014 (UTC)
To avoid these squabbles, we can just note the issue and dispatch the Negative feedback amplifierj, where details are more appropriate. Done. Dicklyon (talk) 18:28, 23 December 2014 (UTC)

An interesting quote[edit]

From Choma & Burgess §6.3 Circuit Partitioning:

"From a purely computational perspective, the preceding section of material is useful for determining the steady-state performance, transient time-domain performance, sensitivity, and stability of practical feedback networks. But from the viewpoint of circuit design, the practicality of the subject material might logically be viewed as dubious, for it promulgates results that depend on unambiguous definitions of the open loop gain and feedback factor. Stated more directly, the results of Section (6.2) are useful only insofar as the transfer function of interest for a given circuit can be framed in the block diagram architecture of Figure 6.1. [The diagram in the WP subsection] Unfortunately, casting a circuit transfer function into the form of Figure 6.1 is a non-trivial task for at least three reasons.
First, neither the open loop amplifier nor the feedback function conducts signals unilaterally. This is to say that amplifiers, and especially amplifiers operated at high signal frequencies, invariably have intrinsic feedback. Moreover, since the feedback sub-circuit is generally a passive network, it is clearly capable of conducting signals from circuit input to circuit output ports, as well as from output to input ports.
Second, the open loop amplifier function is not completely independent of the parameters of the feedback subcircuit, which invariably imposes impedance loads on the amplifier input and output ports.
Third, Figure 6.1 pertains only to global feedback structures. But practical feedback circuits may exploit local feedback; that is, feedback imposed between any two amplifier ports that are not necessarily the output and input ports of the considered system. Local feedback is often invoked purposefully in broadband analog signal processing applications. On the other hand, parasitic local feedback is commonly encountered in high-frequency systems because of energy storage parasitics associated with proximate on-chip signal lines, bond wire interconnects and packaging.
Fortunately, theoretical techniques advanced originally by Kron [21,22] exist to address this engineering dilemma. As is illustrated below, these techniques, which are now embodied into modern circuit partitioning theory [23], have been shown to be especially utilitarian in feedback circuit applications [24]."
[21] G. Kron, Tensor Analysis of Networks. New York: John Wiley & Sons, 1939.
[22] G. Kron, “A set of principles to interconnect the solutions of physical systems”, Journal of Applied Physics, vol. 24, pp. 965–980, August 1953.
[23] R. A. Rohrer, “Circuit partitioning simplified”, IEEE Transactions on Circuits and Systems, vol. 35, pp. 2–5, January 1988.
[24] J. Choma, Jr., “Signal flow analysis of feedback networks”, IEEE Transactions on Circuits and Systems, vol. CAS-37, pp. 455–463, April 1990

Brews ohare (talk) 17:42, 20 December 2014 (UTC)

Choma and Burgess say "casting a circuit transfer function into the form of Figure 6.1 is a non-trivial task" but in fact it can prove impossible. Brews ohare (talk) 17:46, 20 December 2014 (UTC)

There it is. Since nobody is disputing any of that, we can agree to agree. What's your point? Dicklyon (talk) 20:27, 20 December 2014 (UTC)
See point 3 in list of points in previous thread. Brews ohare (talk) 01:44, 21 December 2014 (UTC)
Which in the previous thread you still fail to clarify, and which has unknown relationship to this thread. Dicklyon (talk) 01:53, 21 December 2014 (UTC)
They key point in Choma's list of problems with the two two-port approach in the above quote is the distinction between local and global feedback. This distinction also is pointed out by Palumbo & Pennisi. Where local feedback is employed, a break-up of the feedback amplifier into a forward two-port block and a return feedback two-port block is, as Choma puts it "difficult, if not impossible".
The pertinence of this point to the formulation of the article is obvious to me - the division of the amplifier into these two blocks is applicable only to particular cases, even if the blocks are generalized from unilateral blocks to bilateral two-port blocks.
Can you agree that this point indicates a limitation of the WP treatment using the diagram? And that such a limitation should be pointed out as a caution to the reader that there is more to this topic, and that more general approach can be found in Jaeger, in Gray & Meyer, in Choma & Chen, in Palumbo & Pennisi and elsewhere? Brews ohare (talk) 03:06, 21 December 2014 (UTC)
Choma seems to be saying "not impossible", yet you are concluding the opposite? Or am I missing something? Dicklyon (talk) 03:15, 21 December 2014 (UTC)
The phrase "daunting, if not impossible" can be taken as "daunting, perhaps even impossible", or as "daunting, though perhaps not impossible". Inasmuch as we have examples where so far no two two-port representation has been found, it's all a bit moot. Few will see much future in trying to try to prove a particular example is impossible. What they will do after a few tries is to move on to other faster methods where there is no need for two two-ports. Brews ohare (talk) 04:43, 21 December 2014 (UTC)

Signal flow graphs[edit]

A simple negative feedback system employing two unilateral blocks
Possible signal-flow graph for the asymptotic gain model

In this edit Dicklyon removed the remark:

Methods of analysis based upon signal-flow analysis that do not make these idealizations have been developed, and are discussed in various articles, for example, Return ratio, Asymptotic gain model, Extra element theorem and Negative feedback amplifier.

with the one-line edit summary These uncommented additions don't even make sense, since signal flow grpahs are inherently unidirectional.

Aside from the demeaning tenor of this comment claiming that the removed material doesn't 'even' make sense, this comment includes the irrelevant remark that "signal flow graphs are inherently unidirectional" suggesting, I suppose, that the criticism of the ideal block diagram that it is oversimplified because of its unidirectional nature applies equally to disqualify signal-flow graphs, which because of their unidirectionality also must be viewed as too idealized.

If this is indeed Dicklyon's intention, it is mistaken.

The signal-flow graph, as described in the article Asymptotic gain model is "useful because it completely characterizes feedback amplifiers, including loading effects and the bilateral properties of amplifiers and feedback networks." Moreover, the greater generality of signal flow graphs is the subject of the very well known paper critiquing both the unidirectional and the two-port two-block approaches to amplifiers: J. Choma, Jr. (April 1990). "Signal flow analysis of feedback networks". IEEE Transactions on Circuits and Systems. CAS-37: 455–463.  (On-line here) and as he also comments in the quote above. Similar views are stated by Wai-Kai Chen:

"The third method of feedback circuit analysis exploits Mason's signal flow theory. The circuit level application of this theory suffers few of the shortcomings indigenous to block diagram and two-port methods of feedback circuit analysis. Signal flow analysis applied to feedback networks efficiently express I/O transfer functions, driving point impedance, and driving-point output impedances..."

Inasmuch as two-port block analysis involves bilateral information flow, signal flow graphs are capable of incorporating these effects as well, simply by including arrows that incorporate both directions of flow. Further discussion can be found in Palumbo & Pennisi.

Of course, Dicklyon is entitled to misunderstandings (although they would be cleared up if he chose to read the references provided repeatedly here), but with more humility (or with greater regard for sourcing his opinions) he would not trumpet his gut instincts as if they were decrees from Olympus or perhaps special insights gleaned on Mount Sinai. Brews ohare (talk) 16:29, 29 December 2014 (UTC)

The removed links Return ratio, Asymptotic gain model, Extra element theorem, and the removed perspective that the signal-flow analysis is more general than the unilateral (or bilateral for that matter) two-block diagram both reduce the value of this article in guiding the reader to what WP contains. Brews ohare (talk) 17:04, 29 December 2014 (UTC)

The signal flow graph is an interconnection of unidirectional blocks and summing junctions. I understand your points about why that can be a good approach. The Negative feedback amplifier article would be a good place to introduce this material. I removed the distraction about two-ports to make a cleaner linkage. Dicklyon (talk) 06:30, 30 December 2014 (UTC)
Dick, this is not an introduction to this material - it is guidance for the reader so they can find such an introduction elsewhere, and it is is spread over several articles, and is not discussed in the article Negative feedback amplifier. The reader also needs enough information to understand why they might find these other articles of interest, especially if they are new to the subject. Brews ohare (talk) 06:34, 30 December 2014 (UTC)
I'm saying that if you need to discuss it, then Negative feedback amplifier would be a much more appropriate place. Why would you introduce it here, and not there? Dicklyon (talk) 06:41, 30 December 2014 (UTC)
Dick, although it might be sensible to have a discussion of signal-flow approaches to the amplifier in the article Negative feedback amplifier, at the moment that is not the situation. Instead we have many articles like Return ratio, Asymptotic gain model, Blackman's theorem where signal flow analysis is applied to particular aspects of feedback amplifiers. So, until matters change in WP coverage, the reader is served by pointing out the relevance of these articles for their consideration. Simply providing no indication of what is up, and referring the reader to negative feedback amplifier, where these topics are in fact not discussed but referred again to other articles, gives the reader of Negative feedback no idea of the nature of the oversimplifications made in this subsection, or if they are something the reader might (or might not) find interesting. That guidance takes exactly one sentence, yet you consider it 'bloat'.
Dick, you no longer argue that this added guidance to the reader doesn't even make sense. You simply object to assisting readers to find their way around in WP. Is that advisable? Why should your personal penchant for brevity prevail over WP objectives? Brews ohare (talk) 15:04, 30 December 2014 (UTC)

Repeated refusal to guide the reader[edit]

This talk page is replete with editor suppression of single-sentence additions to this article that say how other WP articles may be relevant to a reader interested in negative feedback. The reason given for this opposition is not that the provided sources and links are incorrect or misleading, but that even one-sentence guidance to other WP articles is 'bloat' that unnecessarily lengthens the article. It is patently ridiculous to suggest that WP articles cannot support short links to other WP articles relevant to a topic, or citations to sources where details can be found, and portraying such a single sentence addition as a 'discussion' best moved to a specialized article is, shall we say, gross distortion.

I fail to see how this radical insistence upon elimination of single-sentence guidance with WP links to other WP articles serves WP or its readers, or how this penchant for brevity is anything but imposition of a personal aesthetic, unsupported by WP policy or guidelines. Brews ohare (talk) 18:14, 30 December 2014 (UTC)

You do not understand how Wikipedia works. Articles are connected primarily by inline wikilinks. It's how a wiki works. In particular it is how this wiki works. Articles can be linked in other ways but this is exceptional and not part of the article content. And article might have links in a see also section. It might have a navbox or infobox with links. It might be written in summary style with short sections with {{main}} links to other articles. But it needs none of these, and there are many good and probably featured articles with none. An article does need inline wikilinks, and these are the primary, and should be the only way within content, of linking to other articles.
So write the article so it describes the topic. Then where possible link to other articles, not too many so only to relevant articles, usually only once at the first mention. Never refer to articles directly as you were doing. In particular don't write "Wikipedia articles" (or "Wikipedia" anything except in its own article) as it makes no sense when articles are mirrored on other encyclopaedias.--JohnBlackburnewordsdeeds 00:53, 31 December 2014 (UTC)
Blackburne, I don't understand your comment. For one example, what is going on here is in-line linkage to other WP articles as you seem to recommend, for example, to signal flow graph as it pertains to negative feedback and is described in return ratio, asymptotic gain model, Blackman's theorem, Extra element theorem and so forth, whose mere linkage as a heads up to the reader is objected to by Dicklyon as unwarranted digression. Perhaps you could explain specifically what is objectionable about the reverted sentence containing these links? I think it is helpful to a reader to be told that the presented discussion is over-simple and more complete methods are described in these other WP articles. There is no attempt to go into detail, just links with a few words to help the reader decide whether they could fit their interests. Brews ohare (talk) 02:03, 31 December 2014 (UTC)
I know you don't understand it, that's clear from your editing. I'm sorry if my further explanation doesn't help. Here is the WP content guideline on such references: Wikipedia:Manual of Style/Self-references to avoid.--JohnBlackburnewordsdeeds 02:12, 31 December 2014 (UTC)
Blackburne: Just love your collegiate tone! However, your link to using WP to self-reference its own validity indicates a misunderstanding of the issue here. The reference to the article Return ratio, for example, is not a use of WP to support its own take on the subject in lieu of published sources, but is only a heads-up to the reader that there is more on WP concerning approaches to the negative feedback amplifier. As support (a different matter than just a flag or a 'table-of-contents' thing) sources are cited like Choma, Chen, Palumbo, etc. (see above).
If you were to read and refer directly to the removed material instead of working on hypothetical abstract assumptions that are divorced entirely from concrete instance, confusion due to your erroneous conception of the issues would not occur. Brews ohare (talk) 03:16, 31 December 2014 (UTC)