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  1. #1
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    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.

    •   Alt25th March 2006, 05:21

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  2. #2
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    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


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    •   Alt25th March 2006, 05:41

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  3. #3
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    noise addition matlab

    please tell me how then set SNR in power terms?



    •   Alt25th March 2006, 08:26

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    Matlab question (noise addition)

    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


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    Matlab question (noise addition)

    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


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