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oblivious 2012 年 6 月 10 日
回答済み: Darel 2021 年 8 月 4 日
i am trying to do some simulation of AWGN channel. matlab has a function awgn(x,snr). what kind of snr does it use here? is it Eb/No (average bit energy/power spectral density)? If so, then i know the awgn has a PSD equal to No/2. does that psd in the snr term implies No/2?


Darel 2021 年 8 月 4 日
The function awgn does not use EbNo. It uses SNR, defined in the same manner as the snr() function from the Signal Processing Toolbox: sum of the squared samples of the signal over sum of the squared samples of the noise, where that ratio is converted to dB. Thus, if you created noisy data according to
y = awgn(x, SNR);
you should be able to check that
mySNR = snr(x, y-x)
is about the same as SNR in the first call.

その他の回答 (1 件)

Wayne King
Wayne King 2012 年 6 月 10 日
With the syntax
y = awgn(x,snr);
You generate a white noise vector with a variance of
variance = 10^(-snr/10);
noise = sqrt(variance)*randn(size(x));
If you use 'measured', then awgn actually measures the signal power.
For example:
x = cos(pi/4*(0:99));
y = awgn(x,5,'measured');
In this case the variance of the additive white noise is:
sigp = 10*log10(norm(x,2)^2/numel(x));
snr = sigp-5;
noisep = 10^(snr/10);
noise = sqrt(noisep)*randn(size(x));
  5 件のコメント
Mrutyunjaya Hiremath
Mrutyunjaya Hiremath 2020 年 9 月 13 日
Meaningful Explanation


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