Noise Normalisation
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From: volkanizma2003 on 1 Jul 2010 15:48 >On Jun 29, 3:31=A0pm, "volkanizma2003" ><ozduranvolkan(a)n_o_s_p_a_m.gmail.com> wrote: >> =A0Hi, I have some problems regarding noise normalisation. I have origina= >l >> signal and I want to add a noise. >> >> EbN0db=3D 0.00; >> SNRv=3D10^(EbN0db/10); >> global sigma; >> sigma=3D1/sqrt(SNRv); >> >> b=3Drandn(1,1200); >> gaus=3Dsigma*b; >> >> x=round(randn(1,1200)); % my original signal >> y=gaus % my noise >> z=x+ gauss % original signal + noise >> >> Question 1.) Do I need to normalize the noise for example multiple by 0.1 >> >> z=x+ 0.1*gauss %will it be like this? >> >> is this noise`s phase is equal to my original signal or less than my >> original signal? >> >> Thanks for your time. > >If x is complex why aren't you adding complex noise? > >Greg > Dear Greg, thanks for your time and interest. X is not a complex x is a digital signal. it contains 0 and 1 bits. And I add analog noise signal into my digital signal. should my noise's amplitude is equal to the my original signal's amplitude or less than original signals amplitude. do I need to adjust the noise by multiple with 0.1 By the way, when I use Ofdm, I use complex signals as you know. Do I need to add random complex noise, or just a random noise. thanks volkan.
From: Greg Heath on 2 Jul 2010 08:44 On Jul 1, 3:48 pm, "volkanizma2003" <ozduranvolkan(a)n_o_s_p_a_m.gmail.com> wrote: > >On Jun 29, 3:31=A0pm, "volkanizma2003" > ><ozduranvolkan(a)n_o_s_p_a_m.gmail.com> wrote: > >> =A0Hi, I have some problems regarding noise normalisation. I have > origina= > >l > >> signal and I want to add a noise. > > >> EbN0db=3D 0.00; > >> SNRv=3D10^(EbN0db/10); > >> global sigma; > >> sigma=3D1/sqrt(SNRv); > > >> b=3Drandn(1,1200); > >> gaus=3Dsigma*b; > > >> x=round(randn(1,1200)); % my original signal > >> y=gaus % my noise > >> z=x+ gauss % original signal + noise > > >> Question 1.) Do I need to normalize the noise for example multiple by > 0.1 > > >> z=x+ 0.1*gauss %will it be like this? > > >> is this noise`s phase is equal to my original signal or less than my > >> original signal? > > >> Thanks for your time. > > >If x is complex why aren't you adding complex noise? > > >Greg > > Dear Greg, thanks for your time and interest. X is not a complex x is a > digital signal. it contains 0 and 1 bits. Look again. You are using round(randn), not round(rand). Also, why do you reference phase? > And I add analog noise signal > into my digital signal. should my noise's amplitude is equal to the my > original signal's amplitude or less than original signals amplitude. do I > need to adjust the noise by multiple with 0.1 > > By the way, when I use Ofdm, I use complex signals as you know. Do I need > to add random complex noise, or just a random noise. thanks volkan.- Hide quoted text - > > - Show quoted text - I really don't know why you are doing this. If you want a real-valued binary signal why not sig(sig>=0.5) = 1 sig(sig<0.5) = 0 Greg
From: HardySpicer on 4 Jul 2010 17:17
On Jun 30, 10:40 pm, John <sampson...(a)gmail.com> wrote: > On Jun 29, 3:31 pm, "volkanizma2003" > > > > <ozduranvolkan(a)n_o_s_p_a_m.gmail.com> wrote: > > Hi, I have some problems regarding noise normalisation. I have original > > signal and I want to add a noise. > > > EbN0db= 0.00; > > SNRv=10^(EbN0db/10); > > global sigma; > > sigma=1/sqrt(SNRv); > > > b=randn(1,1200); > > gaus=sigma*b; > > > x= round(randn(1,1200)); % my original signal > > y= gaus % my noise > > z= x+ gauss % original signal + noise > > > Question 1.) Do I need to normalize the noise for example multiple by 0..1 > > > z=x+ 0.1*gauss %will it be like this? > > > is this noise`s phase is equal to my original signal or less than my > > original signal? > > > Thanks for your time. > > 1) You already scaled the noise when you multiplied it by 1/sqrt(SNR) > 2) Adding the noise does not change the phase, only the amplitude > > John Actually it does. |