dfb2.m

阵列信号处理的工具箱

function [sigOut,vd] = dfb2(sigIn, prf, noDopChan)

%DFB2 Doppler filter bank filtering.
%
%--------
%Synopsis:
%  [sigOut,vd] = dfb2(sigIn)
%  [sigOut,vd] = dfb2(sigIn, prf)
%  [sigOut,vd] = dfb2(sigIn, prf, noDopChan)
%
%Description:
%  Doppler filter bank filtering. Modified version of function "dfb".
%  Among others, this function does not take the absolute value of the result.
%  The number of pulses in the input signal must be an even number.
%
%Output and Input:
%  sigOut (RxRadarSigT): Output radar signal.
%  vd (RealScalarT): Doppler speed [m/s].
%  sigIn (RxRadarSigT): Input radar signal.
%  prf (RealScalarT): PRF (Pulse Repetition Frequency).
%  noDopChan (IntScalarT): Number of doppler channels to create.
%
%--------
%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 ...
%  [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.
%
%Software Quality:
%  (About what is done to ascertain software quality. What tests are done.
%   Known bugs.)
%
%Known Bugs:
%  dfb2 does not save information about the performed filtering, which
%  is necessary to make high resolution doppler estimation.
%  The frequencies of the doppler channels are not saved in the output signal.
%  When there are different wavelengths for different CPI:s ...
%
%See Also:
%  dopplerfilt, pulfilt

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Start        : 961120 Fredrik Athley (freath).
%  Latest change: $Date: 2000/10/16 15:20:37 $ $Author: svabj $.
%  $Revision: 1.19 $
% *****************************************************************************


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

if (nargin < 1)
  error('DBT-Error: To few input parameters.')
end

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

arginNo=2;
if (nargin < arginNo)
  prf = [];
end
arginNo = arginNo +1;
if (nargin < arginNo)
  noDopChan = [];
end
arginNo = arginNo +1;


% *************** Pick out some fields from input parameters. ***************

ant = sigIn.antenna;

lambda  = sigIn.waveform.wavelength;

%K = ant.noElem;
XX =  sigIn.signals;
s = sizem(XX);

noPulses    = s(1);
noRangeBins = s(2);
noBeams     = s(3);
noExtras   = s(4);
noCPIs      = s(5);
noTrials    = s(6);


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

if isempty(prf)
  prf = 1;
end%if
if isempty(noDopChan)
  noDopChan = noPulses;
end%if


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

chkdtype(prf, 'RealScalarT')
chkdtype(noDopChan, 'IntScalarT')


% ----------------------------------------------------------------------- %
% Calculate Doppler.
% ----------------------------------------------------------------------- %

if noPulses>1
  s2 = s;
  s2(1) = noDopChan;
  YY = zerosm(s2);

  for trialLoop = 1:noTrials
  for extraLoop = 1:noExtras
  for range=1:noRangeBins
    for cpi=1:noCPIs
      X = getm(XX,':',range,':',extraLoop,cpi,trialLoop);
      Y = fft(X, noDopChan);
      Y = fftshift1(Y);
      YY(':',range,':',extraLoop,cpi,trialLoop) = Y;		% setm
    end%for cpi
    infoStr = sprintf('dfb2: range = %d(%d)\r',range,noRangeBins);
    dbtinfo(infoStr,1);
  end%for range
  dbtinfo('');	%New line.
  end%for extraLoop
  end%for trialLoop

  fd = linspace(-prf/2, prf/2, noDopChan);
  vd = lambda/2*fd;
else
  YY = XX;
end%if

sigOut = sigIn;
sigOut.signals = YY;


%End Of File