function?[y?wn]?=?addwgn（xsnr）
%?function?[Y?WN]?=?ADDWGN（XSNR）
%?X:?1D?input??signal.
%?SNR:?SNR?required?in?dB.
%?Y:?the?output?signal.
%?WN:?Added?noise?（optional?argument）.
%
%?Adds?white?Gaussian?noise?（AWGN）?of?zero?mean?to?1D?signal?x?so?that?the
%?signal-to-noise?ration?is?snr?in?dB.?The?zero-mean?and?unit-variance?WGN
%?is?computed?by?randn?and?then?it?is?scaled?to?maintain?the?required?SNR
%?given?by?‘snr‘?in?the?function?call.?
%?
%?Author:?Sandeep?P?IITM
%?Created?on:?Oct?12?2009
%?Modified?on:?Oct?26?2009

xe?=?sum（x（:）.^2）;?%?Energy?of?the?signal
%?Noise
w?=?randn（size（x））;
w?=?w-mean（w（:））;
we?=?sum（w（:）.^2）;?%?The?energy?of?the?noise
sig?=?sqrt（xe./（10^（snr/10）*we））;?%?scaling?coefficient?to?get?the?desired?snr.
w?=?sig*w;
y?=?x?+?w;
if（nargout?==?2）
????wn?=?w;
end

%?EOF

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2011-05-25?12:11??curvelet_first_generation\
?????文件????????1229??2010-07-09?13:16??curvelet_first_generation\cvt.m
?????文件????????1163??2011-05-25?11:57??curvelet_first_generation\gauss_denoise_cvt1.m
?????文件????????1256??2010-09-20?07:08??curvelet_first_generation\ridgelet.m
?????文件?????????805??2011-05-25?11:44??curvelet_first_generation\addwgn.m
?????文件????????1129??2010-05-25?06:30??curvelet_first_generation\icvt.m
?????文件????????1342??2010-05-19?06:56??curvelet_first_generation\rectopolar_2_cart.m
?????文件????????1110??2010-05-25?06:30??curvelet_first_generation\iridgelet.m
?????文件?????????862??2010-06-24?04:30??curvelet_first_generation\cvt_lasl_2_llas.m
?????文件????????2417??2010-05-25?05:15??curvelet_first_generation\fft_iso_dwt.m
?????文件????????1431??2010-05-05?11:47??curvelet_first_generation\wave_b3spline_fil.m
?????文件?????????947??2010-06-24?04:31??curvelet_first_generation\cvt_llas_2_lasl.m
?????文件?????????484??2010-02-23?16:56??curvelet_first_generation\upsample2.m
?????文件???????51450??2010-05-19?06:56??curvelet_first_generation\barbara_256x256.jpg
?????文件????????1593??2011-02-21?12:44??curvelet_first_generation\local_ridgeletc.c
?????文件????????1245??2011-05-25?11:50??curvelet_first_generation\cvt_nest.m~
?????文件????????1456??2010-09-20?07:08??curvelet_first_generation\local_ridgelet.m
?????文件??????262750??2010-05-19?06:56??curvelet_first_generation\cameraman.tif
?????文件????????1171??2010-03-02?10:00??curvelet_first_generation\on_wavelet_filters.m
?????文件?????????930??2010-02-23?16:44??curvelet_first_generation\cshift1.m
?????文件????????8254??2011-02-21?12:44??curvelet_first_generation\local_ridgeletc.mexglx
?????文件?????????944??2010-07-09?13:21??curvelet_first_generation\local_ridgelet1.m
?????文件????????8007??2010-05-26?11:49??curvelet_first_generation\cvt_th_4_3445_mean_lasl_zero.mat
?????文件??????????22??2010-11-18?06:56??curvelet_first_generation\.d3lphinview
?????文件????????1727??2011-05-25?11:55??curvelet_first_generation\cvt_nest.m
?????文件????????2293??2011-02-25?06:52??curvelet_first_generation\iso_fuwt2_po.m
?????文件?????????533??2010-04-23?06:40??curvelet_first_generation\psnr.m
?????文件????????1182??2010-04-16?05:48??curvelet_first_generation\fast_cconv2.m
?????文件????????1303??2010-03-08?04:14??curvelet_first_generation\iso_iuwt2_po.m
?????文件????????1199??2010-03-02?12:29??curvelet_first_generation\cshift2.m
?????文件????????1484??2010-05-19?06:56??curvelet_first_generation\cart_2_rectopolar.m
............此處省略3個文件信息