White Gaussian Noise

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?
0
Rupika
4/29/2010 11:03:04 PM
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"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
0
ade77
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.
0
TideMan
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?
0
Rupika
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.
0
Mark
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
0
Rupika
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.


0
TideMan
4/30/2010 5:30:52 AM
Rupika Bandara:
You might also take a look at the imnoise() function in the Image
Processing Toolbox.
0
ImageAnalyst
4/30/2010 10:50:43 AM
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