simcherr.m

阵列信号处理的工具箱

function [sigOut,amperr,phaserr,quaderr] = simcherr(sigIn,am,ph,qu)

% *****************************************************************************
%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  function [sigOut,amperr,phaserr,quaderr] = simcherr(sigIn,am,ph,qu)
%
%  Simulates channel errors in the form of amplitude errors, phase errors,
%  and quadrature errors.
%
%  The output amplitude Aout for each sample is
%    Aout = (1+ Aerr)* Ain,
%  where Aerr is the uniformly distributed relative amplitude error and Ain is
%  the input amplitude.
%
%
%  sigOut  (RxRadarSigT) : Radar signal after channel errors
%  amperr  (RealVectorT) : A vector of simulated  amplitude errors
%  phaserr (RealVectorT) : A vector of simulated  phase errors
%  quaderr (RealVectorT) : A vector of simulated  quadrature errors
%  sigIn   (RxRadarSigT) : Radar signal before channel errors
%  am    (RealScalarT) : Max amplitude error max((1+Aerr)) in dB.
%  ph    (RealScalarT) : Max phase error in radians.
%  qu    (RealScalarT) : Max quadrature error in dB.
%
%Known Bugs:
%  1) The input parameter "phaserr" is not used in the code. A constant
%  "phaseerr" is used instead. Is this a typing error?
%  2) There is no loop over different CPI:s or trials.
%

%  Start        : 9xxxxx Fredrik Athley (freath).
%  Latest change: $Date: 2000/10/16 15:21:52 $ $Author: svabj $.
%  $Revision: 1.12 $
% *****************************************************************************

%antenna = sigIn.antenna;
XM = sigIn.signals;
s = sizem(XM);
noPulses    = s(1);
noRangeBins = s(2);
noChannels  = s(3);
noNotUsed   = s(4);
noCPIs      = s(5);
noTrials    = s(6);

signals = zerosm(s);
K = noChannels;

amperr = (10^(am/20)-1)*(2*rand(1,K)-1);
phaseerr = ph*(2*rand(1,K)-1);
quaderr = (10^(qu/20)-1)*(2*rand(1,K)-1);
errvec = (1+amperr).*exp(i*phaseerr);

for trialLoop = 1:noTrials
for cpiLoop = 1:noCPIs
for notUsedLoop = 1:noNotUsed
for rangeLoop=1:noRangeBins
  % ------------  Get signals.  ------------
  X = getm(XM, ':',rangeLoop,':',notUsedLoop,cpiLoop,trialLoop).';
  [r,c] = size(X);
  if r~=noChannels
    X = X.';
  end
    %

  % ------------ Apply amplitude and phase errors.  ------------
  X = full(sparse(diag(errvec))*X);

  % ------------  Simulate I/Q-errors.  ------------
  Xim = imag(X);
  Xre = real(X);
  Xim = full(sparse(diag(1+quaderr))*Xim);
  X = Xre + i*Xim;

  % ------------  Save signals.  ------------
  %signals = setm(signals, X.', ':',rangeLoop,':', ...
  %  notUsedLoop,cpiLoop,trialLoop);
  signals(':',rangeLoop,':',notUsedLoop,cpiLoop,trialLoop) = X.';
end%for rangeLoop
end%for notUsedLoop
end%for cpiLoop
end%for trialLoop

sigOut = sigIn;  % Must copy all information in the input signal.
sigOut.signals = signals; % Modify part of the input signal.