normcohpulse.m

阵列信号处理的工具箱

function [sigOut, normVec] = normcohpulse(sigIn, method, param1)

%NORMCOHPULSE Makes a radar signal coherent between pulses.
%
%--------
%Synopsis:
%  sigOut = normcohpulse(sigIn)
%  sigOut = normcohpulse(sigIn,[], refRangeBin)
%  sigOut = normcohpulse(sigIn,'refran', refRangeBin)
%  sigOut = normcohpulse(sigIn,'normvec', normVec)
%
%Description:
%  Normalizes the phase of a radar signal to make the signal coherent
%  between pulses.
%
%Output and Input:
%  sigOut (RxRadarSigT) : Radar signal after normalization.
%
%  sigIn (RxRadarSigT) : Radar signal before normalization.
%  refRangeBin [D](IntScalarT): Which range bin to take as reference. 
%    This range bin should contain a strong piece of the transmitted signal
%    and no received signal. Default is 12, since this range bin contains
%    the transmitted puls when using the special measurement arrangements
%    used at FOA in the autumn 1999.
%
%--------
%Notations:
%  Data type names are shown in parentheses and they start with a capital
%  letter and end with a capital T. Data type definitions can be found in [1]
%  or by "help dbtdata".
%  [D] = This parameter can be omitted and then a default value is used.
%  When the [D]-input parameter is not the last used in the call, it must be
%  given the value [], i.e. an empty matrix.
%  ... = There can be more parameters. They are explained under respective
%  metod or choice.
%
%Examples:
%
%Software Quality:
%  (About what is done to ascertain software quality. What tests are done.)
%  Not tested yet.
%
%Known Bugs:
%
%References:
%  [1]: Bj鰎klund S.: "DBT, A MATLAB Toolbox for Radar Signal Processing.
%    Reference Guide", FOA-D--9x-00xxx-408--SE, To be published.
%
%See Also:
%  normsig, uistart

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Start        : 991104 Svante Bj鰎klund (svabj).
%  Latest change: $Date: 2000/10/16 15:21:12 $ $Author: svabj $.
%  $Revision: 1.2 $
% *****************************************************************************


% ----------------------------------------------------------------------- %
% Handle input parameters
% ----------------------------------------------------------------------- %

arginNo=1;
if (nargin < arginNo)
  error('DBT-Error: To few input parameters.')
end%if
arginNo = arginNo +1;


% ****************** Add missing input parameters ******************

if (nargin < arginNo)
  method = [];
end%if
arginNo = arginNo +1;
if (nargin < arginNo)
   param1 = [];
end%if
arginNo = arginNo +1;


% ****************** Default values ******************

if isempty(method)
  method = [];
end%if
if isempty( param1)
   param1 = 14;
     % This range bin contains the transmitted puls when using the
     % special measurement arrangements used at FOA in the autumn 1999.
end%if


% ****************** Error check input parameters ******************

chkdtype(sigIn, 'RxRadarSigT')
chkdtype(param1, 'IntScalarT')

% ****************** Create output variable ******************

sigOut = sigIn;


% ----------------------------------------------------------------------- %
% RxRadarSigT: Radar signals.
% ----------------------------------------------------------------------- %



  % ****************** Signal size ******************

  sizeSpec = sizem(sigIn.signals);
  noPulses = sizeSpec(1);	
  noRanges = sizeSpec(2);
  noChannels = sizeSpec(3);
  noExtras = sizeSpec(4);
  noCPIs   = sizeSpec(5);
  noTrials = sizeSpec(6);



if (1)
  normVec = exp(-j*angle(squeeze(sigIn.signals(:,param1,1))));
    % Get the phase of the reference range bin in each PRI.
    % Use antenna channel 1.
  normMat = repmat(normVec(:), [1, sizeSpec(2:6)]);
    % Create a large matrix with corrections for the following multiplication.
  sigOut.signals = sigOut.signals .* normMat;
    % By element-wise multiplication the signal is normed so that the
    % reference range bin in all PRIs will have the same phase (in our case 
    % phase zero).

else
  disp('oldcoh')

% This code is not finnished.
 
  AntennaChannel = 1;

  % ****************** Loops ******************

  for trialLoop = 1:noTrials
    for cpiLoop = 1:noCPIs
      for extraLoop = 1:noExtras
        for rangeLoop = 1:noRanges
          %sigMat = getm3(sigIn.signals, 3, [], ':',rangeLoop, ':', ...
          %  extraLoop, cpiLoop, trialLoop);
   
          norm = exp(-j*angle(squeeze(sigIn.signals(:,param1,...
            AntennaChannel)))) * ones(1,size(sigIn.signals,3));
          for k = 1:size(sigIn.signals,2)
            sigIn.signals(:,k,:) = squeeze(sigIn.signals(:,k,:)).*norm;
          end%for

          %sigOut.signals(:,rangeLoop,:,extraLoop,cpiLoop,...
          %  trialLoop) = sigOut.signals(:,rangeLoop,:,extraLoop,cpiLoop,...
          %  trialLoop) / sqrt(noisePower);
          %  % Normalize the signal to the noise amplitude.
        end%for rangeLoop
      end%for extraLoop
      infoStr = sprintf(['normcohpulse: cpiLoop = %d(%d), ',...
        'rangeLoop = %d(%d)\r'], cpiLoop, noCPIs, rangeLoop, noRanges);
      dbtinfo(infoStr,1);
    end%for cpiLoop
    dbtinfo('');	%New line.
  end%for trialLoop

end%if (1)