May 8, 2011 #1 M mohammadriyaz.g Newbie level 6 Joined May 8, 2011 Messages 11 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,283 Activity points 1,342 i wanted to add awgn of -140db to the ,psd of other signals in matlab .How to generate or add awgn of -140 db to that psd.I don't have any snr value to use awgn(x,snr )function.plz suggest me
i wanted to add awgn of -140db to the ,psd of other signals in matlab .How to generate or add awgn of -140 db to that psd.I don't have any snr value to use awgn(x,snr )function.plz suggest me
May 9, 2011 #2 C Communications_Engineer Advanced Member level 3 Joined Oct 10, 2008 Messages 894 Helped 179 Reputation 358 Reaction score 105 Trophy points 1,323 Location Sindh, Pakistan Activity points 5,542 1. convert -140dB into linear scale. Say it is NoiPow 2. let Sig is a vector containing your other signals 3. In Matlab type Noise = [randn(1,length(Sig))+j*randn(1,length(Sig))]/sqrt(2); NoisySignal = Sig + Noise*sqrt(NoiPow) I hope I have not made a mistake here. by the way, a noise of -140dB is too small. I wonder how much power your signal has. If it is large -140dB should not cause you any trouble.
1. convert -140dB into linear scale. Say it is NoiPow 2. let Sig is a vector containing your other signals 3. In Matlab type Noise = [randn(1,length(Sig))+j*randn(1,length(Sig))]/sqrt(2); NoisySignal = Sig + Noise*sqrt(NoiPow) I hope I have not made a mistake here. by the way, a noise of -140dB is too small. I wonder how much power your signal has. If it is large -140dB should not cause you any trouble.
May 9, 2011 #3 M mohammadriyaz.g Newbie level 6 Joined May 8, 2011 Messages 11 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,283 Activity points 1,342 what is "j" (red colour)in the given noise expression? Noise = [randn(1,length(Sig))+j*randn(1,length(Sig))]/sqrt(2);
what is "j" (red colour)in the given noise expression? Noise = [randn(1,length(Sig))+j*randn(1,length(Sig))]/sqrt(2);
May 9, 2011 #4 C Communications_Engineer Advanced Member level 3 Joined Oct 10, 2008 Messages 894 Helped 179 Reputation 358 Reaction score 105 Trophy points 1,323 Location Sindh, Pakistan Activity points 5,542 sqrt(-1), to generate complex white noise
May 10, 2011 #5 C commworld Junior Member level 1 Joined May 27, 2010 Messages 17 Helped 2 Reputation 4 Reaction score 2 Trophy points 1,283 Location India Activity points 1,392 can u tell me whats the significance of the 'complex' noise?
May 11, 2011 #6 C Communications_Engineer Advanced Member level 3 Joined Oct 10, 2008 Messages 894 Helped 179 Reputation 358 Reaction score 105 Trophy points 1,323 Location Sindh, Pakistan Activity points 5,542 if your transmission is complex i.e. real and quadrature, the complex white noise is used to add noise to both the component parts
if your transmission is complex i.e. real and quadrature, the complex white noise is used to add noise to both the component parts