I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% and 10% noise to signal ratio) to impact force signals and the acceleration response time histories. Can anyone give me a help?

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4/29/2010 11:03:04 PM

"Rupika Bandara" <rupika23@yahoo.com> wrote in message <hrd378$4e$1@fred.mathworks.com>... > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% and 10% noise to signal ratio) to impact force signals and the acceleration response time histories. Can anyone give me a help? if you have communications toolbox: doc awgn doc wgn

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4/29/2010 11:17:05 PM

On Apr 30, 11:03=A0am, "Rupika Bandara" <rupik...@yahoo.com> wrote: > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% a= nd 10% noise to signal ratio) to impact force signals and the acceleration = response time histories. Can anyone give me a help? For a single percentage: y1=3Dy + pc/100*std(y)*randn(length(y),1); I'll leave to you the upgrading of this into a matrix equation to compute all the pcs at once.

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4/29/2010 11:21:19 PM

TideMan <mulgor@gmail.com> wrote in message <ec0f1675-e601-4583-9888-83ff192fd004@a18g2000prd.googlegroups.com>... > On Apr 30, 11:03 am, "Rupika Bandara" <rupik...@yahoo.com> wrote: > > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% and 10% noise to signal ratio) to impact force signals and the acceleration response time histories. Can anyone give me a help? > > For a single percentage: > y1=y + pc/100*std(y)*randn(length(y),1); > > I'll leave to you the upgrading of this into a matrix equation to > compute all the pcs at once. Hi, Sorry. I am not good at Matlab. So can you explain me further. what is std (is it standard deviation), what is the meaning of randn, and length (y). my force vectors are [100 300 700 800]. Then how can I add 1%, 2%, 5% and 10% noise to signal ratio to these forces?

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4/30/2010 3:40:23 AM

"Rupika Bandara" <rupika23@yahoo.com> wrote in message <hrdjf7$llb$1@fred.mathworks.com>... > TideMan <mulgor@gmail.com> wrote in message <ec0f1675-e601-4583-9888-83ff192fd004@a18g2000prd.googlegroups.com>... > > On Apr 30, 11:03 am, "Rupika Bandara" <rupik...@yahoo.com> wrote: > > > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% and 10% noise to signal ratio) to impact force signals and the acceleration response time histories. Can anyone give me a help? > > > > For a single percentage: > > y1=y + pc/100*std(y)*randn(length(y),1); > > > > I'll leave to you the upgrading of this into a matrix equation to > > compute all the pcs at once. > > Hi, > Sorry. I am not good at Matlab. So can you explain me further. what is std (is it standard deviation), what is the meaning of randn, and length (y). my force vectors are [100 300 700 800]. Then how can I add 1%, 2%, 5% and 10% noise to signal ratio to these forces? Type help std, help randn, help length from the command line. Or read http://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/getstart.pdf or one of the numerous introductory books available.

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4/30/2010 3:59:06 AM

"ade77 " <ade100a@gmail.com> wrote in message <hrd41h$m01$1@fred.mathworks.com>... > "Rupika Bandara" <rupika23@yahoo.com> wrote in message <hrd378$4e$1@fred.mathworks.com>... > > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, 5% and 10% noise to signal ratio) to impact force signals and the acceleration response time histories. Can anyone give me a help? > > if you have communications toolbox: > doc awgn > doc wgn Hi, I went through doc awgn. The first option is Y = AWGN(X,SNR) What does SNR mean? Is it signal to noise ratio? If yes can I use y=awgn(100,0.01) to add 1% noise to 100N force? Can you please give me an idea? Rupika

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4/30/2010 4:01:21 AM

On Apr 30, 4:01=A0pm, "Rupika Bandara" <rupik...@yahoo.com> wrote: > "ade77 " <ade1...@gmail.com> wrote in message <hrd41h$m0...@fred.mathwork= s.com>... > > "Rupika Bandara" <rupik...@yahoo.com> wrote in message <hrd378$4...@fre= d.mathworks.com>... > > > I want to add white Gaussian noise of four intensities (i.e. 1%, 2%, = 5% and 10% noise to signal ratio) to impact force signals and the accelerat= ion response time histories. Can anyone give me a help? > > > if you have communications toolbox: > > doc awgn > > doc wgn > > Hi, > I went through doc awgn. The first option is Y =3D AWGN(X,SNR) > What does SNR mean? Is it signal to noise ratio? If yes can I use y=3Dawg= n(100,0.01) to add 1% noise to 100N force? Can you please give me an idea? > > Rupika Time for YOU to do some work, buster. RTFM. I for one don't have the patience to spoon-feed you. After all, your professor gets paid to do that. We don't.

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4/30/2010 5:30:52 AM

Rupika Bandara: You might also take a look at the imnoise() function in the Image Processing Toolbox.

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4/30/2010 10:50:43 AM

Hi anybdy have any idea how can a baseband audio sound can be supressed or jammed using a white gaussian noise and how the result can be shown in Matlab. any help will be appreciated. -Shruti ...

Hi, I am a newbie in matlab and dsp. I have a signal and would like to generate gaussian noise and use a gaussian filter to remove the noise. From what i have gathered from matlab, to generate gaussian noise i would use randn(1,256) to generate gaussian noise and add it to my signal. However, i am not certain on how to remove the gaussian noise i have generated. Any help is greatly appreciated on how to generate the filter. My code would be : noise=radn(1,256); signal=orginalsignal.*noise; Thanks. Newbie ...

In one signal waveform has been normalized by flicker noise as below. f= 0:100; % frequency points fn = 100; % Nyquist rate F= f/fn; % frequency vector M= abs(100./sqrt(f)); % normalized fequency response M= [zeros(1,6),M(6:100)]; % bound from zero frequency [b1,a1] = yulewalk(3,F,M); % generate order=3 filter And then using this b1,a1 co efficient graph has been drawn, I want to do same thing using any other noise like white Gaussian noise or other, how can I do it? I am from IT back ground so don't know well how to play with signals, please help.... Have you looked at the randn() function? ...

Hi, everyone: I generated a 2-D matrix with spatially-uniform Gaussian White noise. Then I fourier transformed the matrix to frequency domain, and sub-sampled it by a factor of 4. Since the the sampling rate is only 1/4 of Nyquist, there will be aliasing in the new matrix. So the new noise distribution is no longer spatially uniform. But will this non-uniform spatial distribution change the power spectrum density of original white noise? Can I say that the resultant noise is not white noise? Thanks a lot! On Sep 1, 5:19=A0am, "sheng fang" <maelstro...@gmail.com> wrot...

Hi, I used wgn function generate a white Gaussian noise sequences. I had thought the sequences' spectrum is like a white noise , but I finded that the spectrum is like noise. This confuse me much . Could you comment on this? Thanks a lot. here is how I call wgn function: my_noise=wgn(1,1024,1,'linear'); "agump xiaoyong" <agump123@gmail.com> wrote in message news:gjfde6$m9r$1@fred.mathworks.com... > Hi, I used wgn function generate a white Gaussian noise sequences. I had > thought the sequences' spectrum is like a white noise , but I finded > that the spectrum is like noise. This confuse me much . Could you comment > on this? Thanks a lot. here is how I call wgn function: > my_noise=wgn(1,1024,1,'linear');" I am not sure I understand you. But may be you are thinking that white noise is Gaussian noise? May be this from wikipedia might help http://en.wikipedia.org/wiki/White_noise "It is often incorrectly assumed that Gaussian noise (i.e., noise with a Gaussian amplitude distribution - see normal distribution) is necessarily white noise, yet neither property implies the other. Gaussianity refers to the probability distribution with respect to the value i.e. the probability that the signal has a certain given value, while the term 'white' refers to the way the signal power is distributed over time or among frequencies." I do not have the communication toolbox, and the wgn comman...

Hi, I'm having trouble with the randn function. I'm trying to generate a white gaussian noise from -10<a<10 with zero mean and variance 1. I did the following: a=-10:10; noise=randn(size(a)); However, this doesn't seem to be correct. The noise that i get when i plot it, doesn't start at -10, it starts at zero. How can I shift it so that it goes from -10 to 10? Another question, when I check the mean and variance of the signal using the following: meannoise = mean(noise); varnoise = var(noise); The result that I get is not 0 mean and variance 1, why is that? I thought...

Hi I have some real time data collected from a system. I want to do a white noise test on this data and see this data resembles a white noise. I now in SAS software Kilmogorov Simrnov test could be used as white noise test. How do I use the kstest in matlab for checking the white noise effect. Thanks Hi, You can use the kstest in matlab but you will need the Statistical Toolbox for that. But I am not sure what you would what CDF you would use to test your data. Maybe Peter Perkins, would have some suggestions ?? You test the magnitude values of the septrum of your signal (white should be...

does additive white gaussian noise only change the amplitude of a signal or does it change both amplitude and phase? Going from off the top of my head here, so correct me if I am up the garden path on a frosty morn. Gaussian noise is continuous frequency spectrum (ie not discrete frequencies) at random positions in time, thus should not have a phase. As far as the amplitude goes, if you multiply noise by 2, its amplitude becomes larger (doubles). And, if you add it to itself, with no time delay, then it is the same as multiplying by 2. However, if you add 2 seperate lots of equivalent am...

Hi everybody, I want to call the "Gaussian White Noise.vi" several times (lets say, in a loop) and thereby, I want to fully control the state of the random generator which is used in the VI. I think, that the "seed" input somehow determines the state of internal random generator (which is unfortunately "hidden" in a DLL). So, what I would like to have is an output parameter that returns the last state of the random generator . The idea is, that I can call the VI several times setting the "seed" input parameter equal to the state of the random generator of the last call. By this, I could get a reproducible stream of random numbers by simply setting the "seed" input parameter of the first call to a user defined value.I hope, I was able to explain my wishes.Thanks for all repliesStefan<a href="http://dict.leo.org/ende?lp=ende&p=thMx..&search=repeat" target="_blank"></a> Hello, I'm not sure exactly what you are asking, how to do that, or will it work? The how should be a while loop with a shift register. The shift register will store your previous value, feed it into the seed input and will then store the output. It seems a little ironic that you would want a reproduceable set of random numbers, but you are correct in stating that the seed determines the random number. To get the random number generated, that's a little more rough.&...

I'm working on a GUI for PID tuning. My prof told me to add white gaussian noise with variable mean and variance. But I work with tranfer functions and I NEED to know the transfer function of the noise to close the loop and watch controller and filter's action. This can be easily done with Simulink, but I would have to change radically my GUI..please tell me there's another way.. TNX ANTRO ...

Hello all, I'm in need of a C program which implements the Gaussian white noise algorithm in C. The program is to accept a binary file as input and alter it according to the algorithm. I'm affraid this project must run on Windoze :( Thank you in advance Jess "Jess" <jessex@kmfms.com> wrote in message news:63bbea8b.0312070148.4a07e00@posting.google.com... > Hello all, > > I'm in need of a C program which implements the Gaussian white noise > algorithm in C. The program is to accept a binary file as input and > alter it according to the algorithm. ...

How do I add white Gaussian noise to a signal without using the awgn function? For example, i need to add SNR of 5 to a signal x = cos(2*pi*50*t)? "Chang " <chang14@hotmail.com> wrote in message <gm7gpi$jhn$1@fred.mathworks.com>... > How do I add white Gaussian noise to a signal without using the awgn function? > For example, i need to add SNR of 5 to a signal x = cos(2*pi*50*t)? You can use the randn function. You just need to figure out what variance you need to get the desired SNR (in dB). /JC Ok, does this look correct? sig1 = cos(2*pi*50*t) ; energyofsig1...

Hi everyone! I'm trying to calculate the average power of a White Gaussian Noise signal (mean 0, variance 1). All the information I have found is referenced to Power Spectrum Density through "Pwelch" function. Please Help. Best regards, Alejandro ferminreyes@cantv.net The answer, my friend, is sitting there in your question. You don't need Matlab, you need a textbook on elementary spectral analysis. Derek See the thread "Power Spectrum Scaling" Hope this helps. Greg Alejandro wrote: > Hi everyone! > I'm trying to calculate the average power of a White Gaussian Noise > signal (mean 0, variance 1). All the information I have found is > referenced to Power Spectrum Density through "Pwelch" function. Please > Help. > > Best regards, > > Alejandro > ferminreyes@cantv.net The answer, my friend, is sitting in your question. You need to find a textbook on elementary aspects of spectral analysis. You don't need Matlab. Derek In article <63k60bsdjw31@legacy>, Alejandro <ferminreyes@cantv.net> wrote: > Hi everyone! >I'm trying to calculate the average power of a White Gaussian Noise >signal (mean 0, variance 1). All the information I have found is >referenced to Power Spectrum Density through "Pwelch" function. Please >Help. The Schaum's Outline on signal processing will answer your question. --scott -- "C'est un Nagra. C'est ...

HI May i Know how to introduce white Gaussian noise into speech signal using matlab and how can we change the amplitude of the white Gaussian noise? thanx you ivan look at this recent exposee by CSSMer <rune allnor> <http://groups.google.com/groups?hl=en&lr=lang_en&ie=UTF-8&oe=UTF-8&safe=off&selm=f56893ae.0307040948.aedb1a2%40posting.google.com> us Ivan Low: <SNIP wants to introduce white Gaussian noise into his/her speech signal...> ...

Hi all, I used y=awgn(x,SNR) function in MATLAB 2007 . FOR X=100 SNR=-40 Answers are very different. After getting first answer, if I clear command window and type same values again, it gave different value than first answer. Can anyone explain it to me? "Rupika Bandara" <rupika23@yahoo.com> wrote in message <hrgnsd$b2r$1@fred.mathworks.com>... > Hi all, > I used y=awgn(x,SNR) function in MATLAB 2007 . > FOR X=100 > SNR=-40 > Answers are very different. After getting first answer, if I clear command window and type same values again, it gave di...

I am trying to generate a 2-d white noise sequence whose first 4 moments (mean, std dev, skewness, kurtosis) are given. In general, the desired distribution is non-gaussian. One way to do this is to generate a gaussian sequence and then use a nonlinear transformation. 1. I'm wondering if there're any standard codes that do this. 2. If not, I am having trouble with the translation because matlab's 'randn' does not yield results close enough to gaussian, and for high high desired kurtosis values , the nonlinear transformation (e.g. a hyperbolic function) does not yield repeatable results. Any suggestions ? ashwin kumar "Ashwin Kumar" <kumar3@ecn.purdue.edu> wrote in message news:eec5cff.-1@WebX.raydaftYaTP... > I am trying to generate a 2-d white noise sequence whose first 4 > moments (mean, std dev, skewness, kurtosis) are given. In general, > the desired distribution is non-gaussian. One way to do this is to > generate a gaussian sequence and then use a nonlinear transformation. > > > > > 1. I'm wondering if there're any standard codes that do this. > > > 2. If not, I am having trouble with the translation because matlab's > 'randn' does not yield results close enough to gaussian, and for high > high desired kurtosis values , the nonlinear transformation (e.g. a > hyperbolic function) does not yield repeatable results. > > > Any suggest...

Hi all, i am stuck up with generating code for white gaussian noise generator with variable output noise and variable variance. I designed the code using Monte-Carlo simulation, x(n+1)=[Bx(n) + u][mod P] and then generating random variables U1 and U2 such that, U1=sqrt(-2lnX1) * cos(2pi X2) U1=sqrt(-2lnX1) * sin(2pi X2) but U1 and U2 are having variance 1 and i need variable variance... can anyone please help with this problem !! thanks, cheers... "Amar" <pathak_amar@hotmail.com> wrote in message news:dp1wy1vnh80u@legacy... > Hi all, > i am st...

I was wondering how I could modify the Gaussian White Noise.vi or create a new one that could output a Gaussian signal that could be controlled by varying its mean, std, variance, skewness, and kurtosis. I can change its std but I'm especially having problems trying to control its variance, skewness, and kurtosis. Thanks! I've been working with that VI and I don't believe that it has the options you are looking for. You may have to built a custom VI to do this. If you take a look lower down the line of VIs, you will see that they call a DLL to obtain values. You may need to cal...

Hi Guys, I need to generate gaussian white noise on an integer DSP. I have the fast Numerical Recipes generator but it has a log, a sqrt and divides in it. Does anyone know where I can find one or where I can read about how to write one? Thanks Dimiter Dimiter wrote: > Hi Guys, > > I need to generate gaussian white noise on an integer DSP. > > I have the fast Numerical Recipes generator but it has a log, a sqrt > and divides in it. > > Does anyone know where I can find one or where I can read about how to > write one? This has already been discussed many ti...

the equation has the following form: x'' + 0.25x' + 14.8x=g where g is a contiunous Gaussian white noise? It is very easy to solve this differential equation using ODE45 if g is a constant or a sin or cos function. However, in the case g is a contiunous Gaussian white noise, how to deal with this problem? "Min Gan" <aganmin@yahoo.com.cn> wrote in message <hpfbpg$f1u$1@fred.mathworks.com>... > the equation has the following form: > x'' + 0.25x' + 14.8x=g > where g is a contiunous Gaussian white noise? > It is very easy to solve this differential equation using ODE45 if g is a constant or a sin or cos function. > However, in the case g is a contiunous Gaussian white noise, how to deal with this problem? I do not work with ODEs, but I believe the problem as you've framed it is not solvable. I have difficulty seeing its possible physical relevance as well, but that could just be me. "Mark Shore" <mshore@magmageosciences.ca> wrote in message <hpfcpa$1f7$1@fred.mathworks.com>... > "Min Gan" <aganmin@yahoo.com.cn> wrote in message <hpfbpg$f1u$1@fred.mathworks.com>... > > the equation has the following form: > > x'' + 0.25x' + 14.8x=g > > where g is a contiunous Gaussian white noise? > > It is very easy to solve this differential equation using ODE45 if g is a constant or a sin or cos function. > > However, in ...

Hello, I have a final test tomorrow in Matlab where I have to find phrase hidden in wav file using voise filtering. Idea of the task: There are two audio files - one with secret voice message mixed together with white noise and other with white noise sample. Noise is used only partialy - for example from 3rd 'pich' and is 100 'pich' long. Then that noise part is added at the end of itself to make the new noise as long as the voice message and then it is added to voice message. Goals are as these: Design form in witch you can load and show the voice message and white noise. ...

i want to generate a zero mean white noise in matlab if u know please kindly help me naidu wrote: > > > i want to generate a zero mean white noise in matlab if u know > please > kindly help me to generate N samples of zero-mean white noise use either rand(N, 1)-0.5 randn(N, 1) depending on whether the noise should be normally or Gaussian distributed. Markus "Markus Pichler" <m.pichler@icie.jku.at> wrote in message news:ef2d3fe.0@webx.raydaftYaTP... > naidu wrote: >> >> >> i want to generate a zero mean white noise in matlab if u know &...

I'm using LV 7, and am trying to create a loud stimulus using the uniform white noise vi. I have this working fine, but for another stimulus I would like to have a rise/fall time. Does anyone know how to do this? I am quite new to Labview... > for another stimulus I would like to have a rise/fall time. Do you mean the noise starts out "quiet", gradually gets louder until it peaks, then gradually gets quieter again? Just multiply your noise source by your modulation "volume" control. Les ...

Hi anybdy have any idea how can a baseband audio sound can be supressed or jammed using a white gaussian noise and how the result can be shown in Matlab. any help will be appreciated. -Shruti ...

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