I've seen the wonderful people of this newsgroup debunk crap so well before. I want to know what any of you think of this. I was just shown the following website: http://www.xgtechnology.com/ They've got some pdf file overview here: http://www.xgtechnology.com/documents/xg%20flier.pdf They're claiming 20times the transmission rate with little susceptibility to noise, like in a news story they link to: "Bobier previously presented details of his work at the Telecommunications Industry Association's Ventures 2002 show last July. At the time, Bobier claimed that analog paging channels would be able to transmit data at speeds of up to 150 Mbits/sec. He also began work last summer in reducing a typical TV transmission channel for coaxial cable from 6 MHz to 30 kHz." The website seems scant on details. Does anybody have an idea how they're supposedly accomplishing this?
How does XG technology get 20X transmission rate?
Started by ●March 30, 2004
Reply by ●March 30, 20042004-03-30
Hi John, My quick glance told me that the marketing is bunk but there must be something there because of where the big players are coming from (Nokia, Lucent, CTIA, etc., as referenced in the CommsDesign article http://www.commsdesign.com/story/OEG20030414S0012). However, I can't infer squat about their technique from the marketing dribble. The stuff about getting a TV signal down a cable at 30 kHz is easy - just pump up the power enough and you can use a huge m-ary modulation to blow up the spectral efficiency. Remember Shannon's capacity formula is a function of both SNR and bandwidth. In essence they haven't given enough information to say whether the technique is novel or not. At least that's my quick evaluation - could be completely wrong! Caveat anagnostes. --RY silvagier@yahoo.com (John Silvagier) writes:> I've seen the wonderful people of this newsgroup debunk crap so well > before. I want to know what any of you think of this. > > I was just shown the following website: > http://www.xgtechnology.com/ > > They've got some pdf file overview here: > http://www.xgtechnology.com/documents/xg%20flier.pdf > > They're claiming 20times the transmission rate with little > susceptibility to noise, like in a news story they link to: "Bobier > previously presented details of his work at the Telecommunications > Industry Association's Ventures 2002 show last July. At the time, > Bobier claimed that analog paging channels would be able to transmit > data at speeds of up to 150 Mbits/sec. He also began work last summer > in reducing a typical TV transmission channel for coaxial cable from 6 > MHz to 30 kHz." > > The website seems scant on details. Does anybody have an idea how > they're supposedly accomplishing this?-- % Randy Yates % "...the answer lies within your soul %% Fuquay-Varina, NC % 'cause no one knows which side %%% 919-577-9882 % the coin will fall." %%%% <yates@ieee.org> % 'Big Wheels', *Out of the Blue*, ELO http://home.earthlink.net/~yatescr
Reply by ●March 31, 20042004-03-31
"John Silvagier" <silvagier@yahoo.com> wrote in message news:df7bd523.0403301302.39f99c15@posting.google.com...> I've seen the wonderful people of this newsgroup debunk crap so well > before. I want to know what any of you think of this. > > I was just shown the following website: > http://www.xgtechnology.com/ > > They've got some pdf file overview here: > http://www.xgtechnology.com/documents/xg%20flier.pdf > > They're claiming 20times the transmission rate with little > susceptibility to noise, like in a news story they link to: "Bobier > previously presented details of his work at the Telecommunications > Industry Association's Ventures 2002 show last July. At the time, > Bobier claimed that analog paging channels would be able to transmit > data at speeds of up to 150 Mbits/sec. He also began work last summer > in reducing a typical TV transmission channel for coaxial cable from 6 > MHz to 30 kHz." > > The website seems scant on details. Does anybody have an idea how > they're supposedly accomplishing this?Yeah, the data on the website is really vague. My bogus detector is beeping. The secret might be, like Randy says, lots of power. Let's do some numbers. They say they can do 576kbps of data on a 30KHz channel. If I'm remembering Shannon's law correctly, it is: chan_capacity = B*logbase2(1+SNR) where B = bandwidth If I put the numbers in, I get an SNR (at the receiver) of 58dB, and that assumes operating at the Shannon limit. How do you get 58dB SNR at the receiver over a wireless channel? I'm really dubious. It sounds like it is spread-spectrum with a pilot tone. That is my guess because when you look at the spectrum they show, the "signal" doesn't even look modulated. It just looks like a fat carrier with some phase noise. I think the peak is just some sort of pilot. Then there is this paragraph: "The company has run signal/noise tests in the lab, progressively increasing pink noise in a band 7.5MHz on both sides of the test signal of 100MHz with a data rate up to 66 Mbps with and apparent bandwidth of 400 KHz." Why would you test the capacity by increasing noise *outside* the channel? And why do they use the phrase "apparent bandwidth"? My guess: because they're transmitting in somebody else's channel and trying to pretend it doesn't count as real bandwidth. Remember when the spread-spectrum people convinced everybody that CDMA phones would have 20-30 times the channel capacity of the TDMA phones? It worked long enough to get investment money and to get a large base of CDMA phones installed, even thought the numbers were obvious fabrications. -Kevin
Reply by ●March 31, 20042004-03-31
John Silvagier wrote:> I've seen the wonderful people of this newsgroup debunk crap so well > before. I want to know what any of you think of this. > > I was just shown the following website: > http://www.xgtechnology.com/ > > They've got some pdf file overview here: > http://www.xgtechnology.com/documents/xg%20flier.pdf > > They're claiming 20times the transmission rate with little > susceptibility to noise, like in a news story they link to: "Bobier > previously presented details of his work at the Telecommunications > Industry Association's Ventures 2002 show last July. At the time, > Bobier claimed that analog paging channels would be able to transmit > data at speeds of up to 150 Mbits/sec. He also began work last summer > in reducing a typical TV transmission channel for coaxial cable from 6 > MHz to 30 kHz." > > The website seems scant on details. Does anybody have an idea how > they're supposedly accomplishing this?What a crock! May I indulge myself for once, suspending fair-mindedness and claiming simply that if it makes no sense to me, then it isn't real? I can't put my finger on all the nonsense, and I don't have the text in front of me right now, but one of the bits of nonsense that sticks in my mind is the claim that they achieve noise immunity by allowing the detector to see the signal only for isolated brief instances, thereby blocking most of the noise. It's no secret that effective SNR increases directly with the square root of observation time. XGTech does nothing for its credibility by claiming an inverse relationship. I won't invest. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●March 31, 20042004-03-31
Jerry Avins <jya@ieee.org> writes:> [...] > What a crock! [...]Hey Jerry, I'm glad you commented on this, too, and I agree with you, although my conclusion was a little gentler. What the heck is going on around here? I would've thought 75 percent of comp.dsp would've responded to a post like this. -- % Randy Yates % "Maybe one day I'll feel her cold embrace, %% Fuquay-Varina, NC % and kiss her interface, %%% 919-577-9882 % til then, I'll leave her alone." %%%% <yates@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://home.earthlink.net/~yatescr
Reply by ●March 31, 20042004-03-31
This article has a bit of info: http://www.xgtechnology.com/award1.htm Among the claims is that it has been validated by industry experts. "Jerry Avins" <jya@ieee.org> wrote in message news:406b5fb6$0$3057$61fed72c@news.rcn.com...> John Silvagier wrote: > > > I've seen the wonderful people of this newsgroup debunk crap so well > > before. I want to know what any of you think of this. > > > > I was just shown the following website: > > http://www.xgtechnology.com/ > > > > They've got some pdf file overview here: > > http://www.xgtechnology.com/documents/xg%20flier.pdf > > > > They're claiming 20times the transmission rate with little > > susceptibility to noise, like in a news story they link to: "Bobier > > previously presented details of his work at the Telecommunications > > Industry Association's Ventures 2002 show last July. At the time, > > Bobier claimed that analog paging channels would be able to transmit > > data at speeds of up to 150 Mbits/sec. He also began work last summer > > in reducing a typical TV transmission channel for coaxial cable from 6 > > MHz to 30 kHz." > > > > The website seems scant on details. Does anybody have an idea how > > they're supposedly accomplishing this? > > What a crock! May I indulge myself for once, suspending fair-mindedness > and claiming simply that if it makes no sense to me, then it isn't real? > > I can't put my finger on all the nonsense, and I don't have the text in > front of me right now, but one of the bits of nonsense that sticks in my > mind is the claim that they achieve noise immunity by allowing the > detector to see the signal only for isolated brief instances, thereby > blocking most of the noise. It's no secret that effective SNR increases > directly with the square root of observation time. XGTech does nothing > for its credibility by claiming an inverse relationship. I won't invest. > > Jerry > -- > Engineering is the art of making what you want from things you can get. > ����������������������������������������������������������������������� >
Reply by ●March 31, 20042004-03-31
Jon Harris wrote:> This article has a bit of info: > http://www.xgtechnology.com/award1.htm > > Among the claims is that it has been validated by industry experts.True, but it doesn't say which ones. It cites a conference where the claims were presented, as if that were an endorsement. There's a mattress around that claims to be "endorsed by professionals and recognized by NASA". Well whoop-de-doo! That there were some cops who might recognize me wouldn't attest to my being an upstanding citizen. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●March 31, 20042004-03-31
Randy Yates wrote:> Jerry Avins <jya@ieee.org> writes: > >>[...] >>What a crock! [...] > > > Hey Jerry, I'm glad you commented on this, too, and I agree with you, > although my conclusion was a little gentler. > > What the heck is going on around here? I would've thought 75 percent > of comp.dsp would've responded to a post like this.My house has termites and my car is ten years old. Maybe the rest of the gang is worried about being sued. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●April 1, 20042004-04-01
"Jerry Avins" <jya@ieee.org> wrote in message news:406b6f72$0$3043$61fed72c@news.rcn.com...> Jon Harris wrote: > > > This article has a bit of info: > > http://www.xgtechnology.com/award1.htm > > > > Among the claims is that it has been validated by industry experts. > > True, but it doesn't say which ones. It cites a conference where the > claims were presented, as if that were an endorsement. There's a > mattress around that claims to be "endorsed by professionals and > recognized by NASA". Well whoop-de-doo! That there were some cops who > might recognize me wouldn't attest to my being an upstanding citizen. > > Jerry > -- > Engineering is the art of making what you want from things you can get. > ����������������������������������������������������������������������� >But how can you deny the appraisal by "one company representative" that "anyone sending large amounts of data will soon be able ... to send data 20 times faster." I'm sold. I like this line from the FAQ: "7. Why hasn't anyone else thought of this solution? Because the demand for faster transfer of data combined with the sudden lack of available spectrum is a relatively new problem. Nobody needed a solution like xGCMTM until now. " I never knew there had been such a surplus of spectrum hitherto.
Reply by ●April 2, 20042004-04-02
silvagier@yahoo.com (John Silvagier) wrote in message news:<df7bd523.0403301302.39f99c15@posting.google.com>...> I've seen the wonderful people of this newsgroup debunk crap so well > before. I want to know what any of you think of this. > > I was just shown the following website: > http://www.xgtechnology.com/ > > They've got some pdf file overview here: > http://www.xgtechnology.com/documents/xg%20flier.pdf > > They're claiming 20times the transmission rate with little > susceptibility to noise, like in a news story they link to: "Bobier > previously presented details of his work at the Telecommunications > Industry Association's Ventures 2002 show last July. At the time, > Bobier claimed that analog paging channels would be able to transmit > data at speeds of up to 150 Mbits/sec. He also began work last summer > in reducing a typical TV transmission channel for coaxial cable from 6 > MHz to 30 kHz." > > The website seems scant on details. Does anybody have an idea how > they're supposedly accomplishing this?If you are going to squeeze that much data into a limited amount of spectrum, you are going to need a really good lubricant to ease it in. From the scant information I've seen, I think their trick is to use snake oil. :-) Regards, Steve
