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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.-- 72.255.35.11 ( 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.
70.166.123.49 (
talk) 03:37, 9 February 2010 (UTC)
ῶ —Preceding unsigned comment added by 119.153.61.167 ( talk) 01:01, 17 May 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/?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 217.140.96.21 ( 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.
Aursani ( talk) 12:56, 12 June 2015 (UTC)
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)
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." 71.139.176.47 ( talk) 19:35, 12 December 2012 (UTC)
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.
Aursani ( talk) 13:03, 12 June 2015 (UTC)
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.
Yates ( talk) 16:27, 8 October 2016 (UTC)
Baseband ethernet is, by definition, baseband, yet it does have a carrier. The distinction, in using Manchester coding, (aka. phase modulation) is that the carrier frequency is close to the modulation frequency (data rate). Actually, the carrier frequency is equal to the data rate. The carrier is obviously necessary for CSMA/CD to work. I think this means that some of the definitions in the article need to be redone. Gah4 ( talk) 22:22, 7 January 2019 (UTC)
To me, baseband can mean centered at zero, or modulated such that the bandwidth extends essentially to zero (like baseband Ethernet). I'll look for sources... This book might be useful, discussing various "line codes" including Manchester encoding, which don't quite go down to DC. Dicklyon ( talk) 00:00, 8 January 2019 (UTC)
I followed a link to this article to check that baseband meant what I thought, and having read the article and this discussion, I'm still not sure! Here's what I expected it to mean:
If this is correct, I think it gives us a couple of possible definitions:
In other words it's the basic frequency range of the thing we're trying to transmit, and the frequency range wanted by the subsequent electronics. Frequencies in the baseband signal represent themselves. It's "narrow" in the sense of being no wider than it reasonably needs to be to encode the information, and if it's close to zero then that's because the frequency band of the encoded information is close to zero. And we can define it in terms of its purpose, rather than how many kHz or MHz counts as "narrow" or "close to zero". Musiconeologist ( talk) 20:00, 14 September 2021 (UTC)
I've rewritten the lead to get rid of, or at least be more exact about, close to zero. I've also taken out a lot of other dubious stuff. Spinning Spark 21:05, 15 September 2021 (UTC)
It seems to me that Signal that has a very narrow frequency range near zero leaves out what very narrow is relative to, and also near zero leaves out how near. This question comes up in real baseband signals. Start with traditional phones, which are spec'ed as 300Hz to 3400Hz. OH, 3100Hz is pretty narrow, but 300Hz is a ways from zero. For an actual real case, traditional CATV put broadcast TV frequencies into a coaxial cable, so down to 54MHz. Then later there was need for an uplink for pay-TV cable boxes, so they found space below 54MHz, to add it. The cable system amplifiers have to amplify both directions, so have to separate out the two directions first. Because filters are imperfect, you can't get all that close. In any case, broadband CATV has plenty of room below. In any case, baseband rarely gets close to zero, and rarely is narrow. Gah4 ( talk) 20:11, 11 August 2020 (UTC)
To attempt to answer some of the questionss about this sort of slippery topic.
I have looked at the web for a better definition and so far haven't found one so I'm going to try for a 'more rigorous' definition of baseband and maybe an additional section should be added to appeal to engineers, physicists, and mathematicians. I don't think a perfectly rigorous definition is possible so we resort to some logic and an admittedly heuristic definition.
OK so the first problem is the very first figure in the article as it is, has no figure designator and it needs to be referred to in what should be added to this page. Lets call it Fig. 1 here.
OK so Fig. 1 is actually a spectrum for an analytic signal for which a good wiki article exists. So then to start this new 'more rigorous' heuristic section we must identify Fig 1 as the spectrum of an imaginary (complex or analytic) signal and redraw an additional version as the amplitude spectrum of a real signal, such spectrum as an even function adding its mirror image in a new figure. Then explain that the purpose of an analytic signal is to ignore negative frequencies of real signals for arriving at simpler depictions and analyses as in Fig 1.
OK so then we have an amplitude spectrum which is an even function which is a necessary but not sufficient attribute of a baseband signal. In addition to being an even function, every frequency point in the supported spectral domain has one and exactly one nonzero alias at its negative frequency, of identical magnitude. This works for all forms of modulation except SSB.
So then to try to deal with the SSB case we can add that for a baseband as distinct from its SSB form the spectral third moment about the second moment, is of similar magnitude as the second moment about the mean frequency (zero). This works except for extremely narrowband SSB signals e.g. sinusoids which carry no information beyond steady state frequency and phase. So if we have a spectral standard deviation
and define
then if
this would be an arbitrary exclusion of narrowband SSB signals
So then we verbally exclude narrowband SSB signals such as sinusoids. This final condition being strictly logical regrettably.
The 'regrettability' arises from the fact that a SSB modulation of a sinusoid is another pure sinusoid which has no feature described as baseband. So we have to apply this last attempt using the above equations to actual information bearing signals and any of their modulated representations, which as quasi-stochastic would only be characterised in the frequency domain with spectral density as opposed to a Fourier transform amplitude.
Comments welcome.
— Preceding unsigned comment added by Groovamos ( talk • contribs) 23:48, 7 January 2022 (UTC) Groovamos ( talk) 03:10, 8 January 2022 (UTC)
Who on here said that a formal definition should be required? It seems yours truly just posted a section that indicated a formal definition is not possible, if one cares to read it. I have a Ph.D friend, physics, who read the article yesterday and was confused by it. So would it be worthwhile to tell the reader that a formal definition is not possible, made moot in the SSB case? I think I just explained why.
From comments above may I quote:
"What combination of idiots wrote this article? It makes no sense!"
"I second the opinion. This article is not only useless, but also MISLEADING. The Opening paragraph on the Baseband is totally misleading."
"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?"
"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...."
Maybe one has a constructive comment to add to all this. There are people in the sciences and others who might appreciate that.
Groovamos ( talk) 18:11, 8 January 2022 (UTC)
Oh OK so not clear if the opening sentence change revamped the article and made all ssimilar comments out of date. A sentence not out of date would be any of the ones heard on Friday from one friend with a physics Ph.D., if one cares to reread why I came on here. Groovamos ( talk) 21:19, 9 January 2022 (UTC)
The current Short description range of frequencies occupied by an unmodulated signal
is too long and needs to be shorted per
WP:SDSHORT and formatted correctly per
WP:SDFORMAT. Two attempts to resolve this have just been reverted rather than improved. Please attempt to improve the SD —
GhostInTheMachine
talk to me 22:06, 16 June 2022 (UTC)
It seems that the article Broadband is now only about high-speed internet, and lost is the application to radio (well, TV) transmission and reception, and especially the IF strip required for such receivers. When the bandwidth is large compared to the frequency, and that would be IF for many receivers, it complicates the design. That term then continued on into data communications, but now the original use is lost! Gah4 ( talk) 04:34, 2 May 2023 (UTC)
This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
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.-- 72.255.35.11 ( 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.
70.166.123.49 (
talk) 03:37, 9 February 2010 (UTC)
ῶ —Preceding unsigned comment added by 119.153.61.167 ( talk) 01:01, 17 May 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/?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 217.140.96.21 ( 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.
Aursani ( talk) 12:56, 12 June 2015 (UTC)
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)
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." 71.139.176.47 ( talk) 19:35, 12 December 2012 (UTC)
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.
Aursani ( talk) 13:03, 12 June 2015 (UTC)
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.
Yates ( talk) 16:27, 8 October 2016 (UTC)
Baseband ethernet is, by definition, baseband, yet it does have a carrier. The distinction, in using Manchester coding, (aka. phase modulation) is that the carrier frequency is close to the modulation frequency (data rate). Actually, the carrier frequency is equal to the data rate. The carrier is obviously necessary for CSMA/CD to work. I think this means that some of the definitions in the article need to be redone. Gah4 ( talk) 22:22, 7 January 2019 (UTC)
To me, baseband can mean centered at zero, or modulated such that the bandwidth extends essentially to zero (like baseband Ethernet). I'll look for sources... This book might be useful, discussing various "line codes" including Manchester encoding, which don't quite go down to DC. Dicklyon ( talk) 00:00, 8 January 2019 (UTC)
I followed a link to this article to check that baseband meant what I thought, and having read the article and this discussion, I'm still not sure! Here's what I expected it to mean:
If this is correct, I think it gives us a couple of possible definitions:
In other words it's the basic frequency range of the thing we're trying to transmit, and the frequency range wanted by the subsequent electronics. Frequencies in the baseband signal represent themselves. It's "narrow" in the sense of being no wider than it reasonably needs to be to encode the information, and if it's close to zero then that's because the frequency band of the encoded information is close to zero. And we can define it in terms of its purpose, rather than how many kHz or MHz counts as "narrow" or "close to zero". Musiconeologist ( talk) 20:00, 14 September 2021 (UTC)
I've rewritten the lead to get rid of, or at least be more exact about, close to zero. I've also taken out a lot of other dubious stuff. Spinning Spark 21:05, 15 September 2021 (UTC)
It seems to me that Signal that has a very narrow frequency range near zero leaves out what very narrow is relative to, and also near zero leaves out how near. This question comes up in real baseband signals. Start with traditional phones, which are spec'ed as 300Hz to 3400Hz. OH, 3100Hz is pretty narrow, but 300Hz is a ways from zero. For an actual real case, traditional CATV put broadcast TV frequencies into a coaxial cable, so down to 54MHz. Then later there was need for an uplink for pay-TV cable boxes, so they found space below 54MHz, to add it. The cable system amplifiers have to amplify both directions, so have to separate out the two directions first. Because filters are imperfect, you can't get all that close. In any case, broadband CATV has plenty of room below. In any case, baseband rarely gets close to zero, and rarely is narrow. Gah4 ( talk) 20:11, 11 August 2020 (UTC)
To attempt to answer some of the questionss about this sort of slippery topic.
I have looked at the web for a better definition and so far haven't found one so I'm going to try for a 'more rigorous' definition of baseband and maybe an additional section should be added to appeal to engineers, physicists, and mathematicians. I don't think a perfectly rigorous definition is possible so we resort to some logic and an admittedly heuristic definition.
OK so the first problem is the very first figure in the article as it is, has no figure designator and it needs to be referred to in what should be added to this page. Lets call it Fig. 1 here.
OK so Fig. 1 is actually a spectrum for an analytic signal for which a good wiki article exists. So then to start this new 'more rigorous' heuristic section we must identify Fig 1 as the spectrum of an imaginary (complex or analytic) signal and redraw an additional version as the amplitude spectrum of a real signal, such spectrum as an even function adding its mirror image in a new figure. Then explain that the purpose of an analytic signal is to ignore negative frequencies of real signals for arriving at simpler depictions and analyses as in Fig 1.
OK so then we have an amplitude spectrum which is an even function which is a necessary but not sufficient attribute of a baseband signal. In addition to being an even function, every frequency point in the supported spectral domain has one and exactly one nonzero alias at its negative frequency, of identical magnitude. This works for all forms of modulation except SSB.
So then to try to deal with the SSB case we can add that for a baseband as distinct from its SSB form the spectral third moment about the second moment, is of similar magnitude as the second moment about the mean frequency (zero). This works except for extremely narrowband SSB signals e.g. sinusoids which carry no information beyond steady state frequency and phase. So if we have a spectral standard deviation
and define
then if
this would be an arbitrary exclusion of narrowband SSB signals
So then we verbally exclude narrowband SSB signals such as sinusoids. This final condition being strictly logical regrettably.
The 'regrettability' arises from the fact that a SSB modulation of a sinusoid is another pure sinusoid which has no feature described as baseband. So we have to apply this last attempt using the above equations to actual information bearing signals and any of their modulated representations, which as quasi-stochastic would only be characterised in the frequency domain with spectral density as opposed to a Fourier transform amplitude.
Comments welcome.
— Preceding unsigned comment added by Groovamos ( talk • contribs) 23:48, 7 January 2022 (UTC) Groovamos ( talk) 03:10, 8 January 2022 (UTC)
Who on here said that a formal definition should be required? It seems yours truly just posted a section that indicated a formal definition is not possible, if one cares to read it. I have a Ph.D friend, physics, who read the article yesterday and was confused by it. So would it be worthwhile to tell the reader that a formal definition is not possible, made moot in the SSB case? I think I just explained why.
From comments above may I quote:
"What combination of idiots wrote this article? It makes no sense!"
"I second the opinion. This article is not only useless, but also MISLEADING. The Opening paragraph on the Baseband is totally misleading."
"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?"
"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...."
Maybe one has a constructive comment to add to all this. There are people in the sciences and others who might appreciate that.
Groovamos ( talk) 18:11, 8 January 2022 (UTC)
Oh OK so not clear if the opening sentence change revamped the article and made all ssimilar comments out of date. A sentence not out of date would be any of the ones heard on Friday from one friend with a physics Ph.D., if one cares to reread why I came on here. Groovamos ( talk) 21:19, 9 January 2022 (UTC)
The current Short description range of frequencies occupied by an unmodulated signal
is too long and needs to be shorted per
WP:SDSHORT and formatted correctly per
WP:SDFORMAT. Two attempts to resolve this have just been reverted rather than improved. Please attempt to improve the SD —
GhostInTheMachine
talk to me 22:06, 16 June 2022 (UTC)
It seems that the article Broadband is now only about high-speed internet, and lost is the application to radio (well, TV) transmission and reception, and especially the IF strip required for such receivers. When the bandwidth is large compared to the frequency, and that would be IF for many receivers, it complicates the design. That term then continued on into data communications, but now the original use is lost! Gah4 ( talk) 04:34, 2 May 2023 (UTC)