Talk:Bandwidth (signal processing)

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old question[edit]

Aren't bps-type bandwidths and frequency bandwidths really the same thing? A coax cable can only carry a certain frequency range, or a certain number of bits per second. how do you convert between them? - Omegatron 21:59, Jul 29, 2004 (UTC)

This is given by the Shannon-Hartley theorem. - Omegatron 18:27, Aug 10, 2004 (UTC)

typo?[edit]

English is not my native language, but don't you say "to a great extent" and not "to a great extend"? (in the second to the last paragraph).

Yes, "extend" is the verb, "extent" is the noun.--Orthologist 13:36, 26 February 2007 (UTC)

bandwidth vs. datarate[edit]

I think this mixup of "bandwidth" and "data rate" here is quite bad. Bandwidth in communications is a fixed term measured in Hz - it is related to (but not always 1:1) to the datarate (which you could measure in information/time or Bits/sec).

Yes, the distinction between "bandwidth" and "data rate" can be crucial in some (cascaded) settings, as I have illustrated at...
...to which I would be pleased to see an External Link on this page.Paul Niquette 00:59, 7 December 2006 (UTC)

Bandwidth vs Throughput[edit]

Bandwidth is the frequency, and throughput is actually the Kb/s,Mb/s, etc. If no one disagrees, I will make that change after this discussion posting.

Hmm... I think the term can be used for either. Is that "throughput" before or after encoding? Before or after compression? — Omegatron 19:57, 4 October 2005 (UTC)

Throughput is the amount of data that can be sent over the wire at any particular time. Yes everyone uses the term bandwidth, but it's just not factual. If you are referring to the OSI model with your question, I would think that it would be atleast level 3 or lower, but I am not positive. ymmotrojam 04:40, 12 October 2005 (UTC)

Hi! I do agree that the two terms are not the same though describe related processes. Throughput is indeed the amount of data that can transferred via particular channel. But here is one more confusion regarding the information rate, bandwidth and modulation rate. I would appreciate if anybody read the following:

1. Imagine, the road. The road is your bandwidth. The wider the road the more cars can travel at the same time. One car is a bit of information. So the wider the bandwidth the information bits can bit transferred at a time. We got this one. Cool. Here is one more thing you are to comprise. 2. Assume a road with 4 lines, but we have 2 cars on the garage only! So two lines will be used at a time. Turn on your imagination: a car = a truck with some load. The load is the information we want to transfer. The information rate = the rate of those two trucks. We have more space though! So what we can do is to go to a car rent place to get some more cars. Car rate station is our modulator. Truck is a a carrier we load our information at.We did! Hurray! Now we have to divide the load we are to transfer between 4 cars. As we have 4 lines on the road and 4 trucks the load will be delivered faster as twice as we double our speed. Well, in fact the delivery will be any faster... So when we increase modulation rate.. What I know is that we can adjust signal parameters to recall with particular channel parameters. But how about increase in speed?

Equations[edit]

Bandwidth/SNR, or Bitrate/SNR theoretical limits -- anyone know where they are on wikipedia, and why they're not on this page? -- is it called Shannon's theory or something? Ojw 14:53, 18 October 2005 (UTC)

Shannon-HARTLEY Theorem. Yes, it can be found in Wikipedia. —Preceding unsigned comment added by 77.126.65.213 (talk) 07:23, 28 July 2009 (UTC)

Graph[edit]

It is poor writing style to present a graph with unlabeled axes. I imagine the graph shown has frequency as the horizontal axis, but what does the vertical axis measure? Could the author of the text please label these axes?

--> Vertical axis should be gain in decibel.

Digital bandwidth section[edit]

I removed a clause about "with optimal encoding" in the example about a 32-bit data bus. Digital data buses never use a Shannon-Hartley optimal encoding, since that would require reducing the contrast between symbols to account for the high S/N in the bus -- unless the bus S/N ratio is very bad indeed, bilevel binary logic is less than optimal from the standpoint of channel design.

I also removed the phrase "by the uneducated" because it is smarmy and POV. I, too, wish that the bandwidth/capacity channel were not present in common usage, but it is. zowie 01:11, 23 April 2006 (UTC)

Fractional Bandwidth[edit]

I believe the second sentence of "A commonly used quantity is fractional bandwidth. This is the center frequency of a device divided by its bandwidth. E.g., a device that has a bandwidth of 2 MHz with center frequency 10 MHz will have a fractional bandwidth of 2/10, or 20%." should read "...This is the bandwidth of a device divided by its center frequency...". This makes the definition in agree with the example in the third sentence.

Split proposal[edit]

Whoever proposed it should say here what they have in mind doing about it. I think it's not a bad idea, if we can agree on sensible boundaries that everyone likes. Dicklyon 06:36, 1 September 2006 (UTC)

Agreed if we can get some ideas out and about they might be implmented.
Tokyo Michael 17:09, 5 October 2006 (UTC)

Yes, certainly split the page. -Gphoto 17:59, 24 October 2006 (UTC)

  • Oppose. Having thought it over some more, there's not much here. How about expanding on the various meanings, or the application of the concept to the different fields, and see if it gets large or unwieldy. If so, then split it at that time. Dicklyon 05:00, 27 October 2006 (UTC)

I don't know what should be done with the article, but bandwidth as it relates to computers needs to be examined in much greater detail - e.g. the physics behind data transmission, the economics of bandwidth, the engineering involved etc. Perhaps a separate article like Bandwidth (computing) could be created for this, since it could easily dwarf the article. I still think this page should have a general scope though as it does now rather than being a disambiguation page. Richard001 06:12, 10 December 2006 (UTC)

  • Split: Bandwidth means fundementally different things in the analogue and digital spheres, though they both equate approximately to how much data can be stuffed through a media. Would make more sense to make this page a disambiguation page and have separate articles.
  • Split - Bandwidth has important mutually exclusive meanings. Data rates and capacities versus frequency ranges. --JJLatWiki 17:31, 23 April 2007 (UTC)
  • Split - Bandwith means many different things. I would have this page either be the bits-per-second definition or a disambiguation page listing the bits-per-second meaning, the linear algebra furthest-distance-from-nonzero-to-diagonal definition, and the signal-processing range-of-frequencies definition. Either way, somewhere we should clearly state "Bandwidth has many distinct technical meanings." —Ben FrantzDale (talk) 02:05, 23 January 2008 (UTC)

Simple English[edit]

The article linked on "Simple English" is not just simple; it's completely wrong. Does anyone here who understands anything have an account there to fix it? Dicklyon 15:18, 14 November 2006 (UTC)

Disambig[edit]

I support, for bandwidth can also mean how much a server can take. —The preceding unsigned comment was added by -Slash- (talkcontribs) 20:08, 19 December 2006 (UTC).

I was looking for info on the Bandwidth Theorem; i think a disabiguation page would be a good idea, as clearly the term bandwidth means something different to network anylists and physicists (although they describe related phenomena).

There used to be a link at the very top of each of the articles to the disambiguation page Bandwidth. What happened to it? CosineKitty (talk) 20:04, 23 October 2009 (UTC)

Declining Bandwidth Costs[edit]

Can someone provide a web page or information on the historical decline of bandwidth, say from early '80's through today (perhaps with projections to tomorrow)?

Thank you! R/ Porter Clapp Porter Clapp 19:59, 5 March 2007 (UTC)

To what kind of bandwidth are you referring? Data rate capacity, data count allotments, frequency ranges, or some other definition? And what do you mean by "historical decline"? --JJLatWiki 20:56, 23 May 2007 (UTC)

Hi! I would add the following link to the additional resources section: [1] It contains some very nice and detailed tutorials on telecommunication basics


Confused in "Digital BW"[edit]

I can't understand this sentence:"a digital data bus with a bit rate of 66 Mbit/s on each of 32 separate data lines may properly be said to have a bandwidth of 33 MHz and a capacity of 2.1 Gbit/s " It's because how can 66Mbit/s*33MHz=2.1Gbit/s?? It's there any wrong ? In my opinion, the number of bit of each data should be 66 bits and the bandwidth should be 33MHz then the data rate is gonna be 2.1Gbit/s.. If i get wrong concept on this , pls give me the answer~~ Appreciate! Thanks! —Preceding unsigned comment added by Ryan siow (talkcontribs) 02:41, 1 October 2007 (UTC)

The writer meant that 66 Mbit/s can be sent through a band of 33 MHz; true, but utterly irrelevant to the meaning of bandwidth in this context, as your confused interpretation shows. The data rate is 32*66 M = 2.1 Gbps. Dicklyon 02:48, 1 October 2007 (UTC)
Thanks your answer.But i still can't make it clearly. Would u mind tell me what's that mean of "66Mbps"? Thanks! —Preceding unsigned comment added by Ryan siow (talkcontribs) 05:36, 1 October 2007 (UTC)
66 Mbps or Mbit/s is the bit rate on each wire, in megabits per second. Dicklyon 06:16, 1 October 2007 (UTC)

computer network bandwidth should be split[edit]

The sections of this current page about computer network bandwidth belong in their own separate article. They should be split out, and a disambig. link put at the top of this article. --jacobolus (t) 22:54, 18 October 2007 (UTC)

  • Oppose. You mean moving one short paragraph to a separate article about Digital bandwidth in bit/s? It is important that people from analogue electronics, traditional telecommunications and physics become aware about today's widespread usage of the digital definition. It is also important that computer science people are aware of the original analogue definition in Herz, and are encouraged to use less ambiguous terms such as gross bit rate, throughput or channel capacity. Mange01 00:29, 30 October 2007 (UTC)
No, there's a lot more than that to split out; we should definitely have the articles cross reference each others to achieve the clarity that you speak of. Dicklyon (talk) 22:09, 5 February 2008 (UTC)

I agree with jackobolus that they should be split into:
Analog Bandwidth being a range of frequencies utilized in an application such as an RF communications channel
Digital Bandwidth being the data rate witch differs from throughput (witch should account for transmission overhead) --Douglasmwilliams (talk) 20:43, 13 December 2007 (UTC)

  • Support These are different concepts and should be split Lbgrowl (talk) 00:42, 31 December 2007 (UTC)
  • Oppose. I believe there is room on this page to support all the meanings of bandwidth. Like Mange01, I think the reader should be able to see the various meanings side by side and so become aware of the similarities. Binksternet (talk) 03:01, 10 January 2008 (UTC)
  • Support Analogue bandwidth is a complex topic, with links to control theory. It needs exposition of some analogue concepts totaly irrelevant to someone looking for digital bandiwdth. Digital bandwidth does not deal with similar topics anymore. With multiple digital lines and transmission media, analogue bandwidth in terms information theory and digital technology is not relevant. Where it is (i.e. chanel coding?), a link would be appropriate. 134.225.216.197 (talk)
  • Support – the modern proliferation of things called bandwidth (the digital stuff) is pretty much distracting in an article that wants to try to communicate the traditional meaning. Make a new article to split off the digital stuff. Dicklyon (talk) 05:15, 31 January 2008 (UTC)
  • Support - The digital use of "bandwidth" is definitely an error that has crept into common speech. It is also not correct to say that information rate (digital bw) is proportional to bandwidth (analog) and this should be removed from the entry. Shannon's equation gives C=B*log2(S/N+1), C in bps and B in Hz which appears linear. However for the common case where ultimate noise, N, is thermally rather than interference limited, this is equal to KTB, thus B shows up inside the logged argument and the relationship is no longer linear (proportional). The maximum information capacity situation, the so called Shannon limit, represents this case; where the bandwidth (actual/analog) has been increased greatly and the signal plus noise power is very nearly identical to the noise power; (S/N+1) approximately unity. N6gn (talk) 18:14, 5 February 2008 (UTC)

I went ahead and started the bandwidth (computers) article (the title suggested in the merge tag we were discussing). If someone wants to work on it, or move it, feel free. I'll start pulling those bits out of bandwidth now. Dicklyon (talk) 22:09, 5 February 2008 (UTC)

They should be summarized here, shouldn't they? Richard001 (talk) 00:13, 9 February 2008 (UTC)

Proposal: Disambiguation page[edit]

There are at least three distinct definitions of bandwidth. The fields in which they are used overlap, so it's easy for people to get confused. I propose making Bandwidth redirect to Bandwidth (disambiguation). That page would have text along the lines of "Bandwidth can mean different things in the related fields of digital networks, communications and signal processing, and linear algebra." It would then go on to describe each in brief (sufficiently to distinguish between the bits/sec and range-of-Hz meanings) with links to the appropriate three articles. As it stands, it seems particularly easy for newbies to not see the difference between bits per second and frequency bands. —Ben FrantzDale (talk) 03:08, 21 March 2008 (UTC)

Actually there would not be a need for a redirect to a Bandwidth (disambiguation) page, the disambiguation page could be directly at Bandwidth (see WP:DAB#NAME, "Generic topic"). The current article would have to be moved to Bandwidth (frequency range) or something like that, and all links to Bandwidth changed to the correct page. -- memset (talk) 16:25, 3 April 2008 (UTC)
  • Support Now that the original single Bandwidth article has been split, I feel that it is confusing to the reader trying to find one of the splits. Additionally, the neologism business definition could be split out at the dab page, defined there, and not pasted onto any of the math, network and audio freq articles. Binksternet (talk) 06:14, 21 March 2008 (UTC)
  • Support. The use Bandwidth (computing) is widespread enough to justify a a generic-topic dab page (see WP:DAB#NAME) at Bandwidth. Also, there are still a lot of links pointing to Bandwidth that actually mean Bandwidth (computing), replacing Bandwidth with a disambiguation page would be the best way to clear the confusion. -- memset (talk) 16:25, 3 April 2008 (UTC)

Done. There are a lot of links to fix. —Ben FrantzDale (talk) 02:56, 8 April 2008 (UTC)

FYI, I am currently going through the ambiguous links to Bandwidth and changing them to their appropriate sense. This are a lot of them; it will probably take a couple more weeks to get them all done. CosineKitty (talk) 20:00, 22 June 2008 (UTC)
Yea. I've done a handful of them, but there is a lot more to do. A few aren't clear which meaning is appropriate. —Ben FrantzDale (talk) 21:22, 22 June 2008 (UTC)
I know what you mean. A good example is I found a musical album with Bandwidth in the name, and it was linked. There was nothing to distinguish between a range of frequencies or a bit rate, so I left the link to the disambiguation page. We can bounce ideas off of each other here if you want. (I am watching this page.) CosineKitty (talk) 21:42, 22 June 2008 (UTC)

Survey: bit/s/Hz, (bit/s)/Hz or bit·s−1·Hz−1 as Spectral efficiency unit?[edit]

Please vote at Talk:Eb/N0#Survey on which unit that should be used at Wikipedia for measuring Spectral efficiency. For a background discussion, see Talk:Spectral_efficiency#Bit/s/Hz and Talk:Eb/N0#Bit/s/Hz. Mange01 (talk) 07:21, 16 April 2008 (UTC)

Picture needed[edit]

This article really needs a picture in the overview section. Perhaps some kind soul could start with the image in the electromagnetic spectrum article, simplify it, and add some example bandwidths to it (or instruct me how)? --Jhbdel (talk) 07:20, 18 December 2008 (UTC)


First paragraph uses term bandpass without defining it[edit]

The first paragraph's last sentence

The term baseband bandwidth always refers to the upper cutoff frequency, regardless of whether the filter is bandpass or low-pass.

is confusing because bandpass is a new term that is not defined or linked

--71.197.3.22 (talk) 20:51, 13 September 2012 (UTC)

I have cleaned up this and other issues in the lead. -—Kvng 00:05, 19 September 2012 (UTC)