44 lines
1.2 KiB
Matlab
44 lines
1.2 KiB
Matlab
function signal_out = awgn_channel(signal_in, options)
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%AWGN_CHANNEL Apply additive white Gaussian noise to a signal object.
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arguments
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signal_in
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options.snr_dB (1,1) double = 20
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options.randkey = []
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end
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signal_out = signal_in;
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x = signal_in.signal;
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signalPower = mean(abs(x).^2, 'all'); %or use signal_in.power
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if signalPower == 0
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return
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end
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snrLinear = 10^(options.snr_dB/10);
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noisePower = signalPower / snrLinear;
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if isempty(options.randkey)
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if isreal(x)
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noise = sqrt(noisePower) * randn(size(x));
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else
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noise = sqrt(noisePower / 2) * (randn(size(x)) + 1i * randn(size(x)));
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end
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else
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rs = RandStream('mt19937ar', 'Seed', options.randkey);
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if isreal(x)
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noise = sqrt(noisePower) * randn(rs, size(x));
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else
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noise = sqrt(noisePower / 2) * (randn(rs, size(x)) + 1i * randn(rs, size(x)));
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end
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end
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signal_out.signal = x + noise;
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if isa(signal_out, 'Signal')
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desc = sprintf('AWGN channel with SNR %.2f dB', options.snr_dB);
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meta = struct('snr_dB', options.snr_dB, 'randkey', options.randkey);
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signal_out = signal_out.logbookentry(desc, meta);
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end
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end
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