Talk:Phase shift module

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Could someone who is an expert in advanced electronics offer some revisions or additional text to make this rather technical article a little more comprehensible to the lay reader? Starstylers (talk) 16:46, 23 July 2008 (UTC)[reply]

I don't have much time to edit right now, but I'll try to come back in a few days. While I'm no expert -- after all, I came to this page because I realized I'd never bothered to learn how a phase shifter actually works -- I do have a RF/EE background. A lot of the categorization on this page isn't entirely clear, or even relevant. (For example, a practical passive network is always lossy, and has Noise figure equal to its losses, regardless of whether that network is a phase shifter, a power divider, or just a single shunt resistance.)

The short version is this: The simplest electromagnetic wave one can analyze is one that varies sinusoidally with time, or a harmonic wave. Fortunately, pretty much any complicated wave form can be decomposed into the sum of infinitely many sinusoids using Fourier Analysis. This means that a harmonic wave of some given frequency is all we really have to look at when analyzing a given (linear) circuit. If we presume that the frequency is a variable to be taken for granted (or set in value after the general analysis is over), then a harmonic wave, and every piece of (linear) circuitry it passes through can be analyzed using phasors. That is, we can just talk about a wave of a given amplitude, with a given phase relative to some arbitrary reference phase.

A phase shifter just takes a wave passing in, and changes its phase as it passes through. The simplest way to do this is just to adjust the length of the path a wave passing through must take. For example, a path length of 0, 1, 2, ... etc. wavelengths takes the wave through 0°, 360°, 720°,... (that is, a net 0°) phase shift, while a path length of 1/2, 3/2, 5/2, ... etc. wavelengths takes a wave through a net 180° phase shift. Another way would be to just run the wave past a susceptance which will change the phase by 90°.

If one wanted to rewrite the article to explain it clearly, I'd start by referring the reader to the topic on harmonic waves or Phase (waves), then point out that a phase shifter just changes the phase of a wave coming out of it relative to what it was going in. The question of how it does that would then be the remainder of the article. Most of these categories can then either be footnotes, or vanish completely

-- SickOfNewSNs (talk) 08:24, 23 June 2009 (UTC)[reply]