awgn.m

gps/galileo信号源频谱分析

function [Signal_Noise,Noise] = AWGN(Source,SNR)
global NOISE_POWER;
SIGNAL_SIZE=length(Source);
% SNR1 = 10^(SNR/10);  %将dB转化为十进制
% Ps = sum(Source.^2)/SIGNAL_SIZE;  %发送信号能量
% Ps = Ps/2;
% Pn = Ps/SNR1;  %噪声信号能量
% Sigma = sqrt(Pn); %噪声信号幅度
% Noise = Sigma*randn(1,SIGNAL_SIZE);
snr_ratio=10^(SNR/10);
Ps=NOISE_POWER*snr_ratio;
amplitude=sqrt(Ps*2);
Sigma = sqrt(NOISE_POWER);
Noise = Sigma*randn(1,SIGNAL_SIZE);
Signal_Noise = amplitude*Source+Sigma*randn(1,SIGNAL_SIZE);  %经过0均值高斯白噪声信道的待接收信号