Mar 25, 2006 #1 L lincolndsp Banned Joined Aug 13, 2005 Messages 71 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,288 Location Ukraine Activity points 0 noise addition in matlab How can I accurately add to my signal white gaussian noise of exact SNR in dB (in POWER not voltage terms)? when I use awgn(...) function it seems to me the noise has more power than I set in its SNR parameter.
noise addition in matlab How can I accurately add to my signal white gaussian noise of exact SNR in dB (in POWER not voltage terms)? when I use awgn(...) function it seems to me the noise has more power than I set in its SNR parameter.
Mar 25, 2006 #2 D davyzhu Advanced Member level 1 Joined May 23, 2004 Messages 494 Helped 5 Reputation 10 Reaction score 2 Trophy points 1,298 Location oriental Activity points 4,436 noise addition in matlab Hi, I suggest you use randn(). 1D noise: Code: noise = sqrt(variance)*randn(1, symbols_per_frame ); 2D noise: Code: noise = sqrt(variance)*( randn(1,symbols_per_frame) + j*randn(1,symbols_per_frame) ); Regards, Davy
noise addition in matlab Hi, I suggest you use randn(). 1D noise: Code: noise = sqrt(variance)*randn(1, symbols_per_frame ); 2D noise: Code: noise = sqrt(variance)*( randn(1,symbols_per_frame) + j*randn(1,symbols_per_frame) ); Regards, Davy
Mar 25, 2006 #3 L lincolndsp Banned Joined Aug 13, 2005 Messages 71 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,288 Location Ukraine Activity points 0 noise addition matlab please tell me how then set SNR in power terms?
Mar 25, 2006 #4 D davyzhu Advanced Member level 1 Joined May 23, 2004 Messages 494 Helped 5 Reputation 10 Reaction score 2 Trophy points 1,298 Location oriental Activity points 4,436 Sorry, I am not familiar with awgn(). You may turn to NewsGroup: comp.soft-sys.matlab to ask the question. You can access NewsGroup via groups.google.com Regards, Davy
Sorry, I am not familiar with awgn(). You may turn to NewsGroup: comp.soft-sys.matlab to ask the question. You can access NewsGroup via groups.google.com Regards, Davy
Mar 26, 2006 #5 M mimomod Member level 4 Joined Jan 25, 2006 Messages 77 Helped 22 Reputation 44 Reaction score 7 Trophy points 1,288 Activity points 2,351 Hi lincolndsp, from the formula SNR = 10 * log_10 (P_signal/P_noise) we get (Ps/Pn) = 10^(SNR/10). In my simulation I usually set the power of the input signal Ps equals to 1, then vary the power of the noise (variance). So, Pn = 10^(-SNR/10); noise = sqrt(Pn)*randn(1, symbols_per_frame ); best
Hi lincolndsp, from the formula SNR = 10 * log_10 (P_signal/P_noise) we get (Ps/Pn) = 10^(SNR/10). In my simulation I usually set the power of the input signal Ps equals to 1, then vary the power of the noise (variance). So, Pn = 10^(-SNR/10); noise = sqrt(Pn)*randn(1, symbols_per_frame ); best