HI I have a question: 1). Why do we, in most of the cases, assume a noise to be GAUSSIAN? 2). What are characteristics of Gaussian pulse? 3). what is the difference between "White gaussian Noise (WGN)" & "Additive White gaussian Noise (AWGN)"? Thanks 

Gaussianity QUery
Started by ●September 3, 2004
Reply by ●September 3, 200420040903
Anurag HI I have a question: 1). Why do we, in most of the cases, assume a noise to be GAUSSIAN? >>> cause in most of the real life sitatuation noise is indeed GAUSSIAN. 2). What are characteristics of Gaussian pulse? 3). what is the difference between "White gaussian Noise (WGN)" & "Additive White gaussian Noise (AWGN)"? >>> I Dont know any specific difference between WGN and AWGN ... but AWGN is opposite to MWGN ( m = multiplicative) where in the signal through the channel is found by multiplying gaussian noise with the channel symbols. Hope this helps Tarang _____________________________________ Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer. You need to do a "reply all" if you want your answer to be distributed to the entire group. _____________________________________ About this discussion group: To Join: To Post: To Leave: Archives: http://www.yahoogroups.com/group/matlab More DSPRelated Groups: http://www.dsprelated.com/groups.php3 ________________________________ Yahoo! Groups Links To 

Reply by ●September 3, 200420040903
> I have a question: > > 1). Why do we, in most of the cases, assume a noise to be GAUSSIAN? > >>> cause in most of the real life sitatuation noise is indeed GAUSSIAN. For a formal explanation of your problem, I suggest you read the Central Limit Theorem in any statistic book. It says in summary that the convolution of many stochastic processes tend to produce a Gaussian distribution. > > 2). What are characteristics of Gaussian pulse? > 3). what is the difference between "White gaussian Noise (WGN)" > & "Additive White gaussian Noise (AWGN)"? > > >>> I Dont know any specific difference between WGN and AWGN ... but > AWGN is opposite to MWGN ( m = multiplicative) where in the signal > through the channel is found by multiplying gaussian noise with the > channel symbols. I agree with Tarang. White noise defines a flat spectrum, Additive is how it is incorporated in a Stochastic process. > Hope this helps > > Tarang 
Reply by ●September 4, 200420040904
Gaussian noise is an idealized case. Noise is often assumed to be Gaussian in order to make the math easier to find an analytic solution.  Tarang Dadia <> wrote: > Anurag > > HI > > I have a question: > > 1). Why do we, in most of the cases, assume a noise > to be GAUSSIAN? > >>> cause in most of the real life sitatuation > noise is indeed GAUSSIAN. > 2). What are characteristics of Gaussian pulse? > 3). what is the difference between "White gaussian > Noise (WGN)" > & "Additive White gaussian Noise (AWGN)"? > > >>> I Dont know any specific difference between WGN > and AWGN ... but > AWGN is opposite to MWGN ( m = multiplicative) > where in the signal > through the channel is found by multiplying > gaussian noise with the > channel symbols. > > Hope this helps > > Tarang > > _____________________________________ > Note: If you do a simple "reply" with your email > client, only the > author of this message will receive your answer. > You need to do a > "reply all" if you want your answer to be > distributed to the entire > group. > > _____________________________________ > About this discussion group: > > To Join: > > To Post: > > To Leave: > > Archives: http://www.yahoogroups.com/group/matlab > > More DSPRelated Groups: > http://www.dsprelated.com/groups.php3 > > ________________________________ > Yahoo! Groups Links > > To ===== Juan I. Arvelo, Jr., Ph.D. Johns Hopkins University 11100 Johns Hopkins Rd. Laurel, MD 20723 240.228.4293 __________________________________________________ 

Reply by ●September 5, 200420040905
Hello, Continuing with this discussion , can somebody pls let me know how does noise affect in a practical scenario ( how is it concluded to be multiplicative if this is the case). In a simulation environment , every aspect of a reciever like a matched filter or a equalizer depends on AWGN scenario . How is a multiplicative noise simulated and how is a matched filter or a equalizer created for such a environment ? Pls do reply. Rgds  "Juan I. Arvelo, Jr., Ph.D." <> wrote: > Gaussian noise is an idealized case. Noise is often > assumed to be Gaussian in order to make the math > easier to find an analytic solution. >  Tarang Dadia <> wrote: > > > Anurag > > > > HI > > > > I have a question: > > > > 1). Why do we, in most of the cases, assume a > noise > > to be GAUSSIAN? > > > > > > >>> cause in most of the real life sitatuation > > noise is indeed GAUSSIAN. > > > > > > 2). What are characteristics of Gaussian pulse? > > > > > > 3). what is the difference between "White gaussian > > Noise (WGN)" > > & "Additive White gaussian Noise (AWGN)"? > > > > >>> I Dont know any specific difference between > WGN > > and AWGN ... but > > AWGN is opposite to MWGN ( m = multiplicative) > > where in the signal > > through the channel is found by multiplying > > gaussian noise with the > > channel symbols. > > > > Hope this helps > > > > Tarang > > > > > > > > > > > > > > _____________________________________ > > Note: If you do a simple "reply" with your email > > client, only the > > author of this message will receive your answer. > > You need to do a > > "reply all" if you want your answer to be > > distributed to the entire > > group. > > > > _____________________________________ > > About this discussion group: > > > > To Join: > > > > To Post: > > > > To Leave: > > > > Archives: http://www.yahoogroups.com/group/matlab > > > > More DSPRelated Groups: > > http://www.dsprelated.com/groups.php3 > > > > > > > > > > > > > > ________________________________ > > Yahoo! Groups Links > > > > To > > > > > > ===== > Juan I. Arvelo, Jr., Ph.D. > Johns Hopkins University > 11100 Johns Hopkins Rd. > Laurel, MD 20723 > 240.228.4293 > > __________________________________________________ > __________________________________ 
Reply by ●September 5, 200420040905
Just completing the excellent explanations: >2). What are characteristics of Gaussian pulse? A gaussian function is defined as: f(x) = e^((x^2)/2sigma^2) sigma = standard deviation sigma^2 = variance Consequently, you have a function centered arond zero, simmetric. Sigma is an important parameter in the graph. The area under the curve is: Integ(inf,+inf){f(x)dx} = 1/sqrt(2pi.sigma^2) Considering a normal distribution, which turns the majority of the work in many cases pretty simple: P(x) = (1/sqrt(2pi.sigma^2)).f(x) We get a gaussian function normalized to unit area. The convolution of a gaussian function is another gaussian, the only function which has this property. Hope it helps.  "Juan I. Arvelo, Jr., Ph.D." <> escreveu: > Gaussian noise is an idealized case. Noise is often > assumed to be Gaussian in order to make the math > easier to find an analytic solution. >  Tarang Dadia <> wrote: > > > Anurag > > > > HI > > > > I have a question: > > > > 1). Why do we, in most of the cases, assume a > noise > > to be GAUSSIAN? > > > > > > >>> cause in most of the real life sitatuation > > noise is indeed GAUSSIAN. > > > > > > > > > > > > 3). what is the difference between "White gaussian > > Noise (WGN)" > > & "Additive White gaussian Noise (AWGN)"? > > > > >>> I Dont know any specific difference between > WGN > > and AWGN ... but > > AWGN is opposite to MWGN ( m = multiplicative) > > where in the signal > > through the channel is found by multiplying > > gaussian noise with the > > channel symbols. > > > > Hope this helps > > > > Tarang > > > > > > > > > > > > > > _____________________________________ > > Note: If you do a simple "reply" with your email > > client, only the > > author of this message will receive your answer. > > You need to do a > > "reply all" if you want your answer to be > > distributed to the entire > > group. > > > > _____________________________________ > > About this discussion group: > > > > To Join: > > > > To Post: > > > > To Leave: > > > > Archives: http://www.yahoogroups.com/group/matlab > > > > More DSPRelated Groups: > > http://www.dsprelated.com/groups.php3 > > > > > > > > > > > > > > ________________________________ > > Yahoo! Groups Links > > > > To > > > > > > ===== > Juan I. Arvelo, Jr., Ph.D. > Johns Hopkins University > 11100 Johns Hopkins Rd. > Laurel, MD 20723 > 240.228.4293 > > __________________________________________________ > > >  Yahoo! Groups Sponsor > ~> > Make a clean sweep of popup ads. Yahoo! Companion > Toolbar. > Now with PopUp Blocker. Get it for free! > http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/wHYolB/TM > ~> > > > _____________________________________ > Note: If you do a simple "reply" with your email > client, only the author of this message will receive > your answer. You need to do a "reply all" if you > want your answer to be distributed to the entire > group. > > _____________________________________ > About this discussion group: > > To Join: > > To Post: > > To Leave: > > Archives: http://www.yahoogroups.com/group/matlab > > More DSPRelated Groups: > http://www.dsprelated.com/groups.php3 > Yahoo! Groups Links > > =====  Aurio Gonlez Tenio Mestre em Engenharia Elrica  Telecomunicaes Faculdade de Engenharia Elrica e de Computao  FEEC Universidade Estadual de Campinas  UNICAMP  _______________________________________________________ Yahoo! Acesso Gris  navegue de gra com conex de qualidade! http://br.acesso.yahoo.com/ 