%---------------------------------M2M4-------------------------------------?
clc?
clear?
%?Generate?data.?
M?=?4;?%?QPSK?modulation?order?
Pd?=?500;?%?Length?of?data?
x?=?randint（Pd1M）;?%?Random?bit?stream?
ini_phase?=?pi/4;?%ini_phase?
psksig?=?pskmod（xMini_phase）;?%?PSK?signal?
A?=?2;?%?ampitude?of?signal?
snr_theory?=?-6:2:10;?%?Theoretical?value?of?SNR?
QQ?=?10.^（snr_theory/10）;?%?SNR?in?decimal?
?
for?m?=?1:length（snr_theory）?
????SNR=num2str（snr_theory（m））?
????for?n=1:500?
????????rxsig?=?awgn（psksigsnr_theory（m））;?%?Add?Gaussion?noise?
????????M2?=?mean（rxsig.*conj（rxsig））;?%?Two?order?Moments?
????????M4?=?mean（（rxsig.*conj（rxsig））.^2）;?%?Four?order?Moments?
????????s1?=?sqrt（2*M2.^2-M4）;?
????????s2?=?M2-s1;?
????????snr_est_M2M4（n）?=?10*log10（abs（s1./s2））;?
????????M2M4_snr_est（m）?=?mean（snr_est_M2M4）;?%?estimation?value?
????????snr_est12（n）?=?10.^（snr_est_M2M4（n）/10）;?%?SNR?in?decimal?
????????snr_est2（m）?=?mean（snr_est12）;??
????????NMSE_M2M4（m）?=?mean（（（QQ（m）-snr_est12）/QQ（m））.^2）;?%?Normalized?MSE?
????????STD_M2M4（m）?=?var（snr_est_M2M4）;?%standard?deviation?
????????NB_M2M4（m）?=?mean（（QQ（m）-snr_est12）./QQ（m））;?%?normalized?bias?
????end?
end?
figure（1）?
%plot?estimation?value?
plot（snr_theorysnr_theory）;?
hold?on?
plot（snr_theoryM2M4_snr_est‘-o‘）;?
hold?off?
figure（2）?
%?plot?estimation?NMSE?
semilogy（snr_theoryNMSE_M2M4‘-*‘）?
figure（3）?
%?plot?estimation?STD?
plot（snr_theorySTD_M2M4‘-*‘）?
figure（4）?
%?plot?estimation?NB?
plot（snr_theoryNB_M2M4‘-*‘）?
grid

?屬性????????????大小?????日期????時間???名稱
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?????文件??????88417??2010-03-11?19:59??M2M4method?SNR?estimation\M2M4?snr.pdf

?????文件???????1555??2010-03-15?19:25??M2M4method?SNR?estimation\m2m4.m

?????目錄??????????0??2012-12-07?09:56??M2M4method?SNR?estimation

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????????????????89972????????????????????3