matlab wgn未定义,解决matlab缺少awgn和wgn函数的问题

将以下两个.m文件放到同一文件夹内运行

ps：这两个m文件来自  "MATLABR2009atoolboxcommcomm"

awgn.m

function y=awgn(varargin)

%AWGN Add white Gaussian noise to a signal.

% Y = AWGN(X,SNR) adds white Gaussian noise to X. The SNR is in dB.

% The power of X is assumed to be 0 dBW. If X is complex, then

% AWGN adds complex noise.

%

% Y = AWGN(X,SNR,SIGPOWER) when SIGPOWER is numeric, it represents

% the signal power in dBW. When SIGPOWER is 'measured', AWGN measures

% the signal power before adding noise.

%

% Y = AWGN(X,SNR,SIGPOWER,STATE) resets the state of RANDN to STATE.

%

% Y = AWGN(..., POWERTYPE) specifies the units of SNR and SIGPOWER.

% POWERTYPE can be 'db' or 'linear'. If POWERTYPE is 'db', then SNR

% is measured in dB and SIGPOWER is measured in dBW. If POWERTYPE is

% 'linear', then SNR is measured as a ratio and SIGPOWER is measured

% in Watts.

%

% Example 1:

% % To specify the power of X to be 0 dBW and add noise to produce

% % an SNR of 10dB, use:

% X = sqrt(2)*sin(0:pi/8:6*pi);

% Y = awgn(X,10,0);

%

% Example 2:

% % To specify the power of X to be 3 Watts and add noise to

% % produce a linear SNR of 4, use:

% X = sqrt(2)*sin(0:pi/8:6*pi);

% Y = awgn(X,4,3,'linear');

%

% Example 3:

% % To cause AWGN to measure the power of X and add noise to

% % produce a linear SNR of 4, use:

% X = sqrt(2)*sin(0:pi/8:6*pi);

% Y = awgn(X,4,'measured','linear');

%

% See also WGN, RANDN, and BSC.

% Copyright 1996-2008 The MathWorks, Inc.

% $Revision: 1.9.4.6 $ $Date: 2008/08/22 20:23:43 $

% --- Initial checks

error(nargchk(2,5,nargin,'struct'));

% --- Value set indicators (used for the string flags)

pModeSet = 0;

measModeSet = 0;

% --- Set default values

sigPower = 0;

pMode = 'db';

measMode = 'specify';

state = [];

% --- Placeholder for the signature string

sigStr = '';

% --- Identify string and numeric arguments

for n=1:nargin

if(n>1)

sigStr(size(sigStr,2)+1) = '/';

end

% --- Assign the string and numeric flags

if(ischar(varargin{n}))

sigStr(size(sigStr,2)+1) = 's';

elseif(isnumeric(varargin{n}))

sigStr(size(sigStr,2)+1) = 'n';

else

error('comm:awgn:InvalidArg','Only string and numeric arguments are allowed.');

end

end

% --- Identify parameter signatures and assign values to variables

switch sigStr

% --- awgn(x, snr)

case 'n/n'

sig = varargin{1};

reqSNR = varargin{2};

% --- awgn(x, snr, sigPower)

case 'n/n/n'

sig = varargin{1};

reqSNR = varargin{2};

sigPower = varargin{3};

% --- awgn(x, snr, 'measured')

case 'n/n/s'

sig = varargin{1};

reqSNR = varargin{2};

measMode = lower(varargin{3});

measModeSet = 1;

% --- awgn(x, snr, sigPower, state)

case 'n/n/n/n'

sig = varargin{1};

reqSNR = varargin{2};

sigPower = varargin{3};

state = varargin{4};

% --- awgn(x, snr, 'measured', state)

case 'n/n/s/n'

sig = varargin{1};

reqSNR = varargin{2};

measMode = lower(varargin{3});

state = varargin{4};

measModeSet = 1;

% --- awgn(x, snr, sigPower, 'db|linear')

case 'n/n/n/s'

sig = varargin{1};

reqSNR = varargin{2};

sigPower = varargin{3};

pMode = lower(varargin{4});

pModeSet = 1;

% --- awgn(x, snr, 'measured', 'db|linear')

case 'n/n/s/s'

sig = varargin{1};

reqSNR = varargin{2};

measMode = lower(varargin{3});

pMode = lower(varargin{4});

measModeSet = 1;

pModeSet = 1;

% --- awgn(x, snr, sigPower, state, 'db|linear')

case 'n/n/n/n/s'

sig = varargin{1};

reqSNR = varargin{2};

sigPower = varargin{3};

state = varargin{4};

pMode = lower(varargin{5});

pModeSet = 1;

% --- awgn(x, snr, 'measured', state, 'db|linear')

case 'n/n/s/n/s'

sig = varargin{1};

reqSNR = varargin{2};

measMode = lower(varargin{3});

state = varargin{4};

pMode = lower(varargin{5});

measModeSet = 1;

pModeSet = 1;

otherwise

error('comm:awgn:InvalidSyntax','Syntax error.');

end

% --- Parameters have all been set, either to their defaults or by the values passed in,

% so perform range and type checks

% --- sig

if(isempty(sig))

error('comm:awgn:NoInput','An input signal must be given.');

end

if(ndims(sig)>2)

error('comm:awgn:InvalidSignalDims','The input signal must have 2 or fewer dimensions.');

end

% --- measMode

if(measModeSet)

if(~strcmp(measMode,'measured'))

error('comm:awgn:InvalidSigPower','The signal power parameter must be numeric or ''measured''.');

end

end

% --- pMode

if(pModeSet)

switch pMode

case {'db' 'linear'}

otherwise

error('comm:awgn:InvalidPowerType','The signal power mode must be ''db'' or ''linear''.');

end

end

% -- reqSNR

if(any([~isreal(reqSNR) (length(reqSNR)>1) (isempty(reqSNR))]))

error('comm:awgn:InvalidSNR','The signal-to-noise ratio must be a real scalar.');

end

if(strcmp(pMode,'linear'))

if(reqSNR<=0)

error('comm:awgn:InvalidSNRForLinearMode','In linear mode, the signal-to-noise ratio must be > 0.');

end

end

% --- sigPower

if(~strcmp(measMode,'measured'))

% --- If measMode is not 'measured', then the signal power must be specified

if(any([~isreal(sigPower) (length(sigPower)>1) (isempty(sigPower))]))

error('comm:awgn:InvalidSigPower','The signal power value must be a real scalar.');

end

if(strcmp(pMode,'linear'))

if(sigPower<0)

error('comm:awgn:InvalidSigPowerForLinearMode','In linear mode, the signal power must be >= 0.');

end

end

end

% --- state

if(~isempty(state))

if(any([~isreal(state) (length(state)>1) (isempty(state)) any((state-floor(state))~=0)]))

error('comm:awgn:InvaildState','The State must be a real, integer scalar.');

end

end

% --- All parameters are valid, so no extra checking is required

% --- Check the signal power. This needs to consider power measurements on matrices

if(strcmp(measMode,'measured'))

sigPower = sum(abs(sig(:)).^2)/length(sig(:));

if(strcmp(pMode,'db'))

sigPower = 10*log10(sigPower);

end

end

% --- Compute the required noise power

switch lower(pMode)

case 'linear'

noisePower = sigPower/reqSNR;

case 'db'

noisePower = sigPower-reqSNR;

pMode = 'dbw';

end

% --- Add the noise

if(isreal(sig))

opType = 'real';

else

opType = 'complex';

end

y = sig+wgn(size(sig,1), size(sig,2), noisePower, 1, state, pMode, opType);

wgn.m

function y = wgn(varargin)

%WGN Generate white Gaussian noise.

% Y = WGN(M,N,P) generates an M-by-N matrix of white Gaussian noise.

% P specifies the power of the output noise in dBW.

%

% Y = WGN(M,N,P,IMP) specifies the load impedance in Ohms.

%

% Y = WGN(M,N,P,IMP,STATE) resets the state of RANDN to STATE.

%

% Additional flags that can follow the numeric arguments are:

%

% Y = WGN(..., POWERTYPE) specifies the units of P. POWERTYPE can

% be 'dBW', 'dBm' or 'linear'. Linear power is in Watts.

%

% Y = WGN(..., OUTPUTTYPE); Specifies the output type. OUTPUTTYPE can

% be 'real' or 'complex'. If the output type is complex, then P

% is divided equally between the real and imaginary components.

%

% Example 1:

% % To generate a 1024-by-1 vector of complex noise with power

% % of 5 dBm across a 50 Ohm load, use:

% Y = wgn(1024, 1, 5, 50, 'dBm', 'complex')

%

% Example 2:

% % To generate a 256-by-5 matrix of real noise with power

% % of 10 dBW across a 1 Ohm load, use:

% Y = wgn(256, 5, 10, 'real')

%

% Example 3:

% % To generate a 1-by-10 vector of complex noise with power

% % of 3 Watts across a 75 Ohm load, use:

% Y = wgn(1, 10, 3, 75, 'linear', 'complex')

%

% See also RANDN, AWGN.

% Copyright 1996-2008 The MathWorks, Inc.

% $Revision: 1.11.4.5 $ $Date: 2008/08/01 12:17:45 $

% --- Initial checks

error(nargchk(3,7,nargin,'struct'));

% --- Value set indicators (used for the strings)

pModeSet = 0;

cplxModeSet = 0;

% --- Set default values

p = [];

row = [];

col = [];

pMode = 'dbw';

imp = 1;

cplxMode = 'real';

seed = [];

% --- Placeholders for the numeric and string index values

numArg = [];

strArg = [];

% --- Identify string and numeric arguments

% An empty in position 4 (Impedance) or 5 (Seed) are considered numeric

for n=1:nargin

if(isempty(varargin{n}))

switch n

case 4

if(ischar(varargin{n}))

error('comm:wgn:InvalidDefaultImp','The default impedance should be marked by [].');

end;

varargin{n} = imp; % Impedance has a default value

case 5

if(ischar(varargin{n}))

error('comm:wgn:InvalidNumericInput','The default seed should be marked by [].');

end;

varargin{n} = []; % Seed has no default

otherwise

varargin{n} = '';

end;

end;

% --- Assign the string and numeric vectors

if(ischar(varargin{n}))

strArg(size(strArg,2)+1) = n;

elseif(isnumeric(varargin{n}))

numArg(size(numArg,2)+1) = n;

else

error('comm:wgn:InvalidArg','Only string and numeric arguments are allowed.');

end;

end;

% --- Build the numeric argument set

switch(length(numArg))

case 3

% --- row is first (element 1), col (element 2), p (element 3)

if(all(numArg == [1 2 3]))

row = varargin{numArg(1)};

col = varargin{numArg(2)};

p = varargin{numArg(3)};

else

error('comm:wgn:InvalidSyntax','Illegal syntax.')

end;

case 4

% --- row is first (element 1), col (element 2), p (element 3), imp (element 4)

%

if(all(numArg(1:3) == [1 2 3]))

row = varargin{numArg(1)};

col = varargin{numArg(2)};

p = varargin{numArg(3)};

imp = varargin{numArg(4)};

else

error('comm:wgn:InvalidSyntax','Illegal syntax.')

end;

case 5

% --- row is first (element 1), col (element 2), p (element 3), imp (element 4), seed (element 5)

if(all(numArg(1:3) == [1 2 3]))

row = varargin{numArg(1)};

col = varargin{numArg(2)};

p = varargin{numArg(3)};

imp = varargin{numArg(4)};

seed = varargin{numArg(5)};

else

error('comm:wgn:InvalidSyntax','Illegal syntax.');

end;

otherwise

error('comm:wgn:InvalidSyntax','Illegal syntax.');

end;

% --- Build the string argument set

for n=1:length(strArg)

switch lower(varargin{strArg(n)})

case {'dbw' 'dbm' 'linear'}

if(~pModeSet)

pModeSet = 1;

pMode = lower(varargin{strArg(n)});

else

error('comm:wgn:TooManyPowerTypes','The Power mode must only be set once.');

end;

case {'db'}

error('comm:wgn:InvalidPowerType','Incorrect power mode passed in. Please use ''dBW'', ''dBm'', or ''linear.''');

case {'real' 'complex'}

if(~cplxModeSet)

cplxModeSet = 1;

cplxMode = lower(varargin{strArg(n)});

else

error('comm:wgn:TooManyOutputTypes','The complexity mode must only be set once.');

end;

otherwise

error('comm:wgn:InvalidArgOption','Unknown option passed in.');

end;

end;

% --- Arguments and defaults have all been set, either to their defaults or by the values passed in

% so, perform range and type checks

% --- p

if(isempty(p))

error('comm:wgn:InvalidPowerVal','The power value must be a real scalar.');

end;

if(any([~isreal(p) (length(p)>1) (length(p)==0)]))

error('comm:wgn:InvalidPowerVal','The power value must be a real scalar.');

end;

if(strcmp(pMode,'linear'))

if(p<0)

error('comm:wgn:NegativePower','In linear mode, the required noise power must be >= 0.');

end;

end;

% --- Dimensions

if(any([isempty(row) isempty(col) ~isscalar(row) ~isscalar(col)]))

error('comm:wgn:InvalidDims','The required dimensions must be real, integer scalars > 1.');

end;

if(any([(row<=0) (col<=0) ~isreal(row) ~isreal(col) ((row-floor(row))~=0) ((col-floor(col))~=0)]))

error('comm:wgn:InvalidDims','The required dimensions must be real, integer scalars > 1.');

end;

% --- Impedance

if(any([~isreal(imp) (length(imp)>1) (length(imp)==0) any(imp<=0)]))

error('comm:wgn:InvalidImp','The Impedance value must be a real scalar > 0.');

end;

% --- Seed

if(~isempty(seed))

if(any([~isreal(seed) (length(seed)>1) (length(seed)==0) any((seed-floor(seed))~=0)]))

error('comm:wgn:InvalidState','The State must be a real, integer scalar.');

end;

end;

% --- All parameters are valid, so no extra checking is required

switch lower(pMode)

case 'linear'

noisePower = p;

case 'dbw'

noisePower = 10^(p/10);

case 'dbm'

noisePower = 10^((p-30)/10);

end;

% --- Generate the noise

if(~isempty(seed))

randn('state',seed);

end;

if(strcmp(cplxMode,'complex'))

z = randn(2*row,col);

y = (sqrt(imp*noisePower/2))*(z(1:row,:)+j*z(row+1:end,:));

else

y = (sqrt(imp*noisePower))*randn(row,col);

end;