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(shí)間???名稱
-----------?---------??----------?-----??----
?????文件?????????805??2011-05-25?21:14??curvelet_first_generation\addwgn.m
?????文件???????51450??2010-05-19?16:26??curvelet_first_generation\barbara_256x256.jpg
?????文件??????262750??2010-05-19?16:26??curvelet_first_generation\cameraman.tif
?????文件????????1484??2010-05-19?16:26??curvelet_first_generation\cart_2_rectopolar.m
?????文件?????????537??2010-12-21?17:25??curvelet_first_generation\cell_cardinality.m
?????文件?????????528??2010-12-20?16:24??curvelet_first_generation\cellabs.m
?????文件????????1147??2010-09-20?20:08??curvelet_first_generation\celladd.m
?????文件????????1266??2010-12-20?16:25??curvelet_first_generation\cellcompare.m
?????文件????????1040??2010-09-20?19:33??curvelet_first_generation\celldivide.m
?????文件?????????508??2010-04-22?15:11??curvelet_first_generation\cellmean.m
?????文件????????1178??2010-09-20?20:04??curvelet_first_generation\cellmul.m
?????文件?????????510??2010-05-21?23:31??curvelet_first_generation\cellnegate.m
?????文件?????????563??2011-02-15?19:44??curvelet_first_generation\cellnorm1.m
?????文件?????????582??2011-02-15?19:40??curvelet_first_generation\cellnorm2.m
?????文件?????????530??2011-02-15?20:24??curvelet_first_generation\cellnorms2.m
?????文件?????????415??2010-09-22?01:48??curvelet_first_generation\cellnumel.m
?????文件?????????517??2010-04-20?16:47??curvelet_first_generation\cellpower.m
?????文件?????????526??2010-05-21?00:02??curvelet_first_generation\cellsign.m
?????文件?????????484??2010-04-20?16:12??curvelet_first_generation\cellsquare.m
?????文件????????1191??2010-11-10?22:45??curvelet_first_generation\cellsubtract.m
?????文件?????????930??2010-02-24?03:14??curvelet_first_generation\cshift1.m
?????文件????????1199??2010-03-02?22:59??curvelet_first_generation\cshift2.m
?????文件????????1229??2010-07-09?22:46??curvelet_first_generation\cvt.m
?????文件?????????862??2010-06-24?14:00??curvelet_first_generation\cvt_lasl_2_llas.m
?????文件?????????947??2010-06-24?14:01??curvelet_first_generation\cvt_llas_2_lasl.m
?????文件????????1727??2011-05-25?21:25??curvelet_first_generation\cvt_nest.m
?????文件????????8007??2010-05-26?21:19??curvelet_first_generation\cvt_th_4_3445_mean_lasl_zero.mat
?????文件????????1182??2010-04-16?15:18??curvelet_first_generation\fast_cconv2.m
?????文件????????2417??2010-05-25?14:45??curvelet_first_generation\fft_iso_dwt.m
?????文件????????1963??2010-05-25?15:01??curvelet_first_generation\fft_iso_idwt.m
?????文件????????1155??2012-03-21?18:30??curvelet_first_generation\gauss_denoise_cvt1.m
............此處省略13個(gè)文件信息