|WikiProject Computing / Networking||(Rated C-class, Mid-importance)|
|WikiProject Telecommunications||(Rated C-class, Mid-importance)|
Does ethernet use baseband signaling?
- Yes, it does. Although we don't have that piece of information in an article so far as I can tell. See Ethernet and IEEE 802.3. -Splashtalk 17:54, 14 February 2006 (UTC)
- Not necessarily. The orignal Ethernet used "Manchester coding", which can be viewed as shifting the theoretical 5 MHz baseband of 10 Mbps data up to a carrier frequency of 10 MHz, so the band occupied can be as narrow as 5 to 15 MHz. Due to AC coupling with capacitors and/or transformers at various points, moving the peak of the data spectrum up from 0 to 10 MHz is helpful. This, however, is but one physical implementation of Ethernet. Others such as 802.11 shift it up to RF, of course. Dicklyon 16:30, 19 August 2006 (UTC)
CISCO state the the "base" in 10Base-T refers to baseband and by inference surey this means Ethernet uses baseband.
Let's work on a good opening sentence and definition (current version uses "comprises" in the typical incorrect way, and doesn't get to the point very specifically). It would be good to at least admit that any kind of Fourier analysis gives negative frequencies, too. For real signals, these are just reflections of the positive, not new information, so they are conventionally ignored. And the "RF" spectrum needs to reference double sideband and/or single-sideband modulation to explain where this comes from. I'll see if I can help. Please comment on my attempts. Dicklyon 16:30, 19 August 2006 (UTC)
In typical fashion, this article seems to be geared toward those who would have no reason to look it up on wikipedia in the first place, having already earned their PhDs in engineering. Perhaps it could be made a little less intimidating for the uninitiated.--126.96.36.199 (KartoumHero) 02:25, 16 July 2009 (UTC)
In the Intro, it says "from zero" to the highest frequency. Later on in the article, it doesn't say "from zero" but only to the highest frequency. This article is frustrating for that and other reasons. If you don't know what baseband is to begin with, this article doesn't help. 188.8.131.52 (talk) 03:37, 9 February 2010 (UTC)
What combination of idiots wrote this article? It makes no sense! To be clear, I understand the topic now, but only because I went back to the VERY FIRST draft of this article from 2002 (http://en.wikipedia.org/w/index.php?title=Baseband&oldid=71326)!!! That at least was a clear explanation, especially if read alongside the wikipedia articles for Band and Modulation. I'm afraid to help edit the article though, because I have no idea what the hell the useless drivel on the current version means. Mmurfin (talk) 20:14, 15 August 2010 (UTC)
This article seems to be textbook stuff for students of signal processing theory. There is a specific and widespread usage of "baseband" in mobile telephony (and in phrases such as "baseband modem", "baseband IC") - this article really could benefit from explaining that. Wikipedia's much more useful when it's making sense of fast-moving, real-world concepts than when it's just a substitute for buying a textbook. —Preceding unsigned comment added by 184.108.40.206 (talk) 12:48, 18 November 2010 (UTC)
I second the opinion. This article is not only useless, but also MISLEADING. The Opening paragraph on the Baseband is totally misleading.
Not So Useless, and btw, what's the frequency bandwidth of Ethernet?
I disagree, I see some value here. Go around the web and search for something that connects "Bandwidth" and e.g. "Ethernet". There is so little out there that even many engineers get so confused about something so basic as to claim that an Ethernet signal has no frequency spectrum because it's digital. Granted, it's something engineered once per decade or so, but not digging into this is like not explaining how things work because we're not supposed to understand the guts of a Tamagochi like they used to understand the guts of a spring-driven toy car. And, by the way, can anybody add the real-world (as opposed to information-theory or whatever) spectrum bandwidths of the various Ethernet signals? It' a bit like not mentioning that swimming is a form of locomotion (go see! :-P ) Spamhog (talk) 22:54, 1 December 2010 (UTC)
- In the case of many signals, it isn't useful to give one number as bandwidth. You really need a power spectrum, how much power is transmitted at which frequency. In the case of coaxial ethernet, it gets more complicated. While the data signal might fit in a 5MHz to 15MHz band, collision detection is done it DC, that is, close to 0Hz. The signal on the cable is not AC coupled, and the average DC voltage, after filtering, is used for collision detection. It might be that between 1kHz and 5kHz that you could squeeze in some other signal. Twisted-pair ethernet is transformer coupled, and so can't go down, or even close, to 0Hz. Gah4 (talk) 21:55, 28 March 2017 (UTC)
What is baseband?
Isn't the definition of baseband 'the signal you are trying to transmit'? Maybe add a quick explanation for the lay person, or an example, like: "In AM radio, the baseband includes the announcer's voice. The baseband is then modulated with the carrier frequency, which is the frequency on the radio dial, and then demodulated so that a voice is heard at the receiver." 220.127.116.11 (talk) 19:35, 12 December 2012 (UTC)
- I cannot agree more with this statement. Although replacing the entire article with this talk entry would be a large net improvement, simply offering the above explanation as the first paragraph would at least allay the offensive nature of this article to date. 5000+ people a month are being victimized by this academic fappery. I try not to attribute malice to that which can be explained by the innocent bloviation that comes naturally to experts but articles this bad cause me to wonder if I'm being naive. Allenc28 (talk) 05:56, 13 July 2015 (UTC)
Meaning of Baseband
Transmission of signal with infinite bandwidth is called the basband transmission. A single signal transmitted over the transmission line occupies all the bandwidth of the transmission line. A digital pulse transmitted without modulation occupies infinite bandwidth.
Definition of Baseband
In my experience and opinion, a baseband signal is a signal that is centered at zero (f = 0) when viewing the two-sided (positive and negative) spectrum. It doesn't really have anything to do with bandwidth, as stated in the article.
It is true that when one needs to modulate a signal, the carrier frequency must be chosen based on the bandwidth of the baseband signal and is usually much larger than the bandwidth, but this is a consequence of modulation.
- Just reading the first sentence" Baseband is a signal that has a very narrow and near-zero frequency range, raises questions to me. First of all, very narrow relative to what? 1000baseT, that is, gigabit ethernet, is baseband, though with a bandwidth over 100MHz. And how close does it get to 0Hz? Not very. Seems to me that in actual use, a signal is baseband if its bandwidth is much wider than the frequency of the lower end of the band. That is true for wide (say 10MHz or more) and narrow band signals. The result is that there isn't spectral space for another (frequency shifted) version of the signal at lower frequencies. There might be room for other signals, though. Gah4 (talk) 21:44, 28 March 2017 (UTC)