I am a student in a Telecomm course and was given an assignment for finding the max. data rate of system. I was given a cosine pulse of x(t)= cos(((2*pi)/T)*t). I ran through MathCAD for Fourier transform and attenuation error and phase factor and got a wave form over 500 meters loses about 50% due to Attenuation and a phase shift of about 2.5 MHz or 2.5 microsecond. I am asked to find the data rate of this system and the only thing I find is 1/T where T = 10^-6. this gives me a data rate of 1 MHz. Is it that simple or is there a way I can find the SNR to use Shannon's equation. Thank you for any help for the right direction. Dave
datarate calulations
Started by ●October 5, 2003
Reply by ●October 5, 20032003-10-05
sorry for two post had an error posting first one did not think it went through. "subspaceguns" <rush854@swbell.net> wrote in message news:E9Nfb.2458$q%3.1306@newssvr24.news.prodigy.com...> I am a student in a Telecomm course and was given an assignment forfinding> the max. data rate of system. I was given a cosine pulse of x(t)= > cos(((2*pi)/T)*t). I ran through MathCAD for Fourier transform and > attenuation error and phase factor and got a wave form over 500 metersloses> about 50% due to Attenuation and a phase shift of about 2.5 MHz or 2.5 > microsecond. > > I am asked to find the data rate of this system and the only thing I findis> 1/T where T = 10^-6. this gives me a data rate of 1 MHz. Is it that simple > or is there a way I can find the SNR to use Shannon's equation. > > Thank you for any help for the right direction. > > Dave > > >
Reply by ●October 5, 20032003-10-05
subspaceguns wrote:> sorry for two post had an error posting first one did not think it went > through. > "subspaceguns" <rush854@swbell.net> wrote in message > news:E9Nfb.2458$q%3.1306@newssvr24.news.prodigy.com... > >>I am a student in a Telecomm course and was given an assignment for > > finding > >>the max. data rate of system. I was given a cosine pulse of x(t)= >>cos(((2*pi)/T)*t). I ran through MathCAD for Fourier transform and >>attenuation error and phase factor and got a wave form over 500 meters > > loses > >>about 50% due to Attenuation and a phase shift of about 2.5 MHz or 2.5 >>microsecond. >> >>I am asked to find the data rate of this system and the only thing I find > > is > >>1/T where T = 10^-6. this gives me a data rate of 1 MHz. Is it that simple >>or is there a way I can find the SNR to use Shannon's equation. >> >>Thank you for any help for the right direction. >> >>DaveI have no idea what you did. 2.5 MHz has a period of .4�sec. Conversely, a 2.5 �sec period is that of a 400 KHz waveform. Where does attenuation come in? You left too much out. Jerry -- "I view the progress of science as ... the slow erosion of the tendency to dichotomize." Barbara Smuts, U. Mich. ���������������������������������������������������������������������
Reply by ●October 5, 20032003-10-05
Rush wrote:
> sorry I was tired when I wrote the message. I have attached the
> MathCAD that I ran and I am stuck on finding the what the max.
> theoretic date rate. I would appreciate any help. I think it is just
> the original cos pulse but it can not be that straight forward.
>
> Dave Rush
Dave, I don't read Mathcad well. Moreover, a description of what you
tried to do is more useful than code that didn't do it. We want to know
the statement of the problem and the assumptions that underlie your
proposed solution, as well as the solution itself. Code becomes useful
if the solution seems reasonable but doesn't work.
In general, we try not to do student's homework, but to help them to do
it themselves. Discussing theory and spotting bugs is legitimate help,
but it belongs in the newsgroup.
Be sure you understand what is being asked. The data rate of a
noise-free channel is theoretically infinite. That's not a paradox
because such a channel can't exist. Sophisticated analyses can't proceed
without a noise specification. A baseband or single-sideband system can
support a highest frequency equal to the bandwidth. Setting that equal
to the data rate seems, as you put it, too straightforward, but it would
be my off-hand guess.
Jerry
--
Besides a mathematical inclination, an exceptionally good mastery of
one's native tongue is the most vital asset of a competent programmer.
Edsger W. Dijkstra
-----------------------------------------------------------------------
Reply by ●October 5, 20032003-10-05
I forgot the MathCAD I sent you did do what it was suppose to do and that was just compare the output at 500 meters when Attenuation and phase shift are applied. I used Fourier analysis and inverse Fourier to get the out put wave. Just the second part of the question simply asked what is the theoretic max data rate of the system. I am stuck whether to use the bandwidth of the cosine pulse or the time difference of output and input signal to calculate the Bandwidth with would give the data rate. Dave ----- Original Message ----- From: "Jerry Avins" <jya@ieee.org> Newsgroups: comp.dsp To: "subspaceguns" <rush854@swbell.net> Sent: Sunday, October 05, 2003 12:55 PM Subject: Re: datarate calulations> Rush wrote: > > sorry I was tired when I wrote the message. I have attached the > > MathCAD that I ran and I am stuck on finding the what the max. > > theoretic date rate. I would appreciate any help. I think it is just > > the original cos pulse but it can not be that straight forward. > > > > Dave Rush > > Dave, I don't read Mathcad well. Moreover, a description of what you > tried to do is more useful than code that didn't do it. We want to know > the statement of the problem and the assumptions that underlie your > proposed solution, as well as the solution itself. Code becomes useful > if the solution seems reasonable but doesn't work. > > In general, we try not to do student's homework, but to help them to do > it themselves. Discussing theory and spotting bugs is legitimate help, > but it belongs in the newsgroup. > > Be sure you understand what is being asked. The data rate of a > noise-free channel is theoretically infinite. That's not a paradox > because such a channel can't exist. Sophisticated analyses can't proceed > without a noise specification. A baseband or single-sideband system can > support a highest frequency equal to the bandwidth. Setting that equal > to the data rate seems, as you put it, too straightforward, but it would > be my off-hand guess. > > Jerry > -- > Besides a mathematical inclination, an exceptionally good mastery of > one's native tongue is the most vital asset of a competent programmer. > Edsger W. Dijkstra > ----------------------------------------------------------------------- >"Jerry Avins" <jya@ieee.org> wrote in message news:3F805B25.1030002@ieee.org...> Rush wrote: > > sorry I was tired when I wrote the message. I have attached the > > MathCAD that I ran and I am stuck on finding the what the max. > > theoretic date rate. I would appreciate any help. I think it is just > > the original cos pulse but it can not be that straight forward. > > > > Dave Rush > > Dave, I don't read Mathcad well. Moreover, a description of what you > tried to do is more useful than code that didn't do it. We want to know > the statement of the problem and the assumptions that underlie your > proposed solution, as well as the solution itself. Code becomes useful > if the solution seems reasonable but doesn't work. > > In general, we try not to do student's homework, but to help them to do > it themselves. Discussing theory and spotting bugs is legitimate help, > but it belongs in the newsgroup. > > Be sure you understand what is being asked. The data rate of a > noise-free channel is theoretically infinite. That's not a paradox > because such a channel can't exist. Sophisticated analyses can't proceed > without a noise specification. A baseband or single-sideband system can > support a highest frequency equal to the bandwidth. Setting that equal > to the data rate seems, as you put it, too straightforward, but it would > be my off-hand guess. > > Jerry > -- > Besides a mathematical inclination, an exceptionally good mastery of > one's native tongue is the most vital asset of a competent programmer. > Edsger W. Dijkstra > ----------------------------------------------------------------------- >
Reply by ●October 5, 20032003-10-05
Thank you Jerry, that is my best guess too. since there is not mention of noise in the problem except for Attenuation and a phase shift. I see the data rate as being limited by the bandwidth and since the bandwidth is a cos pulse from 0 to 1 the data rate has to be the bandwidth of the pulse. I was trying to figure out a way to Shannon's equation but without a way to find the SNR I figured the only way to find the data rate was the bandwidth. Thank you for help again I was trying to get someone else to agree with the way I was approaching the problem. "Jerry Avins" <jya@ieee.org> wrote in message news:3F805B25.1030002@ieee.org...> Rush wrote: > > sorry I was tired when I wrote the message. I have attached the > > MathCAD that I ran and I am stuck on finding the what the max. > > theoretic date rate. I would appreciate any help. I think it is just > > the original cos pulse but it can not be that straight forward. > > > > Dave Rush > > Dave, I don't read Mathcad well. Moreover, a description of what you > tried to do is more useful than code that didn't do it. We want to know > the statement of the problem and the assumptions that underlie your > proposed solution, as well as the solution itself. Code becomes useful > if the solution seems reasonable but doesn't work. > > In general, we try not to do student's homework, but to help them to do > it themselves. Discussing theory and spotting bugs is legitimate help, > but it belongs in the newsgroup. > > Be sure you understand what is being asked. The data rate of a > noise-free channel is theoretically infinite. That's not a paradox > because such a channel can't exist. Sophisticated analyses can't proceed > without a noise specification. A baseband or single-sideband system can > support a highest frequency equal to the bandwidth. Setting that equal > to the data rate seems, as you put it, too straightforward, but it would > be my off-hand guess. > > Jerry > -- > Besides a mathematical inclination, an exceptionally good mastery of > one's native tongue is the most vital asset of a competent programmer. > Edsger W. Dijkstra > ----------------------------------------------------------------------- >
Reply by ●October 5, 20032003-10-05
subspaceguns wrote:> I forgot the MathCAD I sent you did do what it was suppose to do and that > was just compare the output at 500 meters when Attenuation and phase shift > are applied. I used Fourier analysis and inverse Fourier to get the out put > wave. Just the second part of the question simply asked what is the > theoretic max data rate of the system. > I am stuck whether to use the bandwidth of the cosine pulse or the time > difference of output and input signal to calculate the Bandwidth with would > give the data rate. > > Dave > ----- Original Message ----- > From: "Jerry Avins" <jya@ieee.org> > Newsgroups: comp.dsp > To: "subspaceguns" <rush854@swbell.net> > Sent: Sunday, October 05, 2003 12:55 PM > Subject: Re: datarate calulations > > > >>Rush wrote: >> > sorry I was tired when I wrote the message. I have attached the >> > MathCAD that I ran and I am stuck on finding the what the max. >> > theoretic date rate. I would appreciate any help. I think it is just >> > the original cos pulse but it can not be that straight forward. >> > >> > Dave Rush >> >>Dave, I don't read Mathcad well. Moreover, a description of what you >>tried to do is more useful than code that didn't do it. We want to know >>the statement of the problem and the assumptions that underlie your >>proposed solution, as well as the solution itself. Code becomes useful >>if the solution seems reasonable but doesn't work. >> >>In general, we try not to do student's homework, but to help them to do >>it themselves. Discussing theory and spotting bugs is legitimate help, >>but it belongs in the newsgroup. >> >>Be sure you understand what is being asked. The data rate of a >>noise-free channel is theoretically infinite. That's not a paradox >>because such a channel can't exist. Sophisticated analyses can't proceed >>without a noise specification. A baseband or single-sideband system can >>support a highest frequency equal to the bandwidth. Setting that equal >>to the data rate seems, as you put it, too straightforward, but it would >>be my off-hand guess. >> >>Jerry >>-- >>Besides a mathematical inclination, an exceptionally good mastery of >>one's native tongue is the most vital asset of a competent programmer. >> Edsger W. Dijkstra >>----------------------------------------------------------------------- >> > > > "Jerry Avins" <jya@ieee.org> wrote in message > news:3F805B25.1030002@ieee.org... > >>Rush wrote: >> > sorry I was tired when I wrote the message. I have attached the >> > MathCAD that I ran and I am stuck on finding the what the max. >> > theoretic date rate. I would appreciate any help. I think it is just >> > the original cos pulse but it can not be that straight forward. >> > >> > Dave Rush >>Dave, There are two reasons to keep these discussions in the newsgroup. One is that my mailbox would fill too fast if I played consultant to the world at large from home. More important to you is that I'm a relatively ignorant consultant (when it comes to DSP) and the august denizens of comp.dsp, looking over our shoulders, stand ready to chant, "Nyah, nyah" (or simply "Wait a minute") if I steer you wrong. You bypass the collective wisdom by writing to me directly. Why don't you ask the instructor what you're expected to do? Jerry -- Besides a mathematical inclination, an exceptionally good mastery of one's native tongue is the most vital asset of a competent programmer. Edsger W. Dijkstra -----------------------------------------------------------------------
Reply by ●October 5, 20032003-10-05
Jerry Avins wrote: I forgot to add that the signal's delay through the medium isn't related to the data rate, but only to the latency. Jerry -- "I view the progress of science as ... the slow erosion of the tendency to dichotomize." Barbara Smuts, U. Mich. ���������������������������������������������������������������������
Reply by ●October 5, 20032003-10-05
thanks, I am a nontraditional student who works fulltime. When I am done with class I go straight to work and when off of work teacher is gone most of the time. I have done very well researching answers to problems that crop up by using the schools library. But, every once in while a simple little problem will stump me. I will ask him tomorrow after the work is turned in. I always to get input from several different sources, this way I hopefully have a better understanding of the problem when it is answered. Anyway thank you, did help a lot. Dave "Jerry Avins" <jya@ieee.org> wrote in message news:blq2se$j41$1@bob.news.rcn.net...> subspaceguns wrote: > > I forgot the MathCAD I sent you did do what it was suppose to do andthat> > was just compare the output at 500 meters when Attenuation and phaseshift> > are applied. I used Fourier analysis and inverse Fourier to get the output> > wave. Just the second part of the question simply asked what is the > > theoretic max data rate of the system. > > I am stuck whether to use the bandwidth of the cosine pulse or the time > > difference of output and input signal to calculate the Bandwidth withwould> > give the data rate. > > > > Dave > > ----- Original Message ----- > > From: "Jerry Avins" <jya@ieee.org> > > Newsgroups: comp.dsp > > To: "subspaceguns" <rush854@swbell.net> > > Sent: Sunday, October 05, 2003 12:55 PM > > Subject: Re: datarate calulations > > > > > > > >>Rush wrote: > >> > sorry I was tired when I wrote the message. I have attached the > >> > MathCAD that I ran and I am stuck on finding the what the max. > >> > theoretic date rate. I would appreciate any help. I think it is just > >> > the original cos pulse but it can not be that straight forward. > >> > > >> > Dave Rush > >> > >>Dave, I don't read Mathcad well. Moreover, a description of what you > >>tried to do is more useful than code that didn't do it. We want to know > >>the statement of the problem and the assumptions that underlie your > >>proposed solution, as well as the solution itself. Code becomes useful > >>if the solution seems reasonable but doesn't work. > >> > >>In general, we try not to do student's homework, but to help them to do > >>it themselves. Discussing theory and spotting bugs is legitimate help, > >>but it belongs in the newsgroup. > >> > >>Be sure you understand what is being asked. The data rate of a > >>noise-free channel is theoretically infinite. That's not a paradox > >>because such a channel can't exist. Sophisticated analyses can't proceed > >>without a noise specification. A baseband or single-sideband system can > >>support a highest frequency equal to the bandwidth. Setting that equal > >>to the data rate seems, as you put it, too straightforward, but it would > >>be my off-hand guess. > >> > >>Jerry > >>-- > >>Besides a mathematical inclination, an exceptionally good mastery of > >>one's native tongue is the most vital asset of a competent programmer. > >> Edsger W. Dijkstra > >>----------------------------------------------------------------------- > >> > > > > > > "Jerry Avins" <jya@ieee.org> wrote in message > > news:3F805B25.1030002@ieee.org... > > > >>Rush wrote: > >> > sorry I was tired when I wrote the message. I have attached the > >> > MathCAD that I ran and I am stuck on finding the what the max. > >> > theoretic date rate. I would appreciate any help. I think it is just > >> > the original cos pulse but it can not be that straight forward. > >> > > >> > Dave Rush > >> > Dave, > > There are two reasons to keep these discussions in the newsgroup. One is > that my mailbox would fill too fast if I played consultant to the world > at large from home. More important to you is that I'm a relatively > ignorant consultant (when it comes to DSP) and the august denizens of > comp.dsp, looking over our shoulders, stand ready to chant, "Nyah, nyah" > (or simply "Wait a minute") if I steer you wrong. You bypass the > collective wisdom by writing to me directly. > > Why don't you ask the instructor what you're expected to do? > > Jerry > -- > Besides a mathematical inclination, an exceptionally good mastery of > one's native tongue is the most vital asset of a competent programmer. > Edsger W. Dijkstra > ----------------------------------------------------------------------- >
Reply by ●October 5, 20032003-10-05
subspaceguns wrote:> thanks, I am a nontraditional student who works fulltime. When I am done > with class I go straight to work and when off of work teacher is gone most > of the time.... It sort of seemed that way. I went to night school for a while. Jerry -- "I view the progress of science as ... the slow erosion of the tendency to dichotomize." Barbara Smuts, U. Mich. ���������������������������������������������������������������������
