expsig1.m

阵列信号处理的工具箱

function sigvar = expsig1(antenna, signalFileName, measIndex, snapshots, dbName, measName, pModulation)

%EXPSIG1 Reads antenna signals measured with the AIMT experimental antenna.
%
%--------
%Synopsis:
%  sigvar = expsig1(antenna, signalFileName, measIndex, snapshots)
%  sigvar = expsig1(antenna, signalFileName, measIndex, snapshots, dbName,
%                   measName, pModulation)
%
%Description:
%  Reads antenna signals measured with the AIMT experimental antenna [2].
%  Can read signals both from passive (listen-only mode) and active mode
%  (radar mode) [3].
%
%  Signals in passive and active are stored and interpreted differently. 
%  In passive mode the subscripts are (timeIx, 1, channelIx, extraIx, 1, 
%  trialIx). In active mode the subscripts are (pulseIx, timeInPulseIx, 
%  channelIx, extraIx, cpiIx, trialIx). See [1] for more information.
%
%  In passive mode several meaurements can be stored in the trialIx
%  dimension. In active mode this is not possible. In active mode there
%  can be several pulses and alla pulses are read at once. 
%  Several pulses is not possible in passive mode.
%  
%  The signals must have been down-converted with a factor 4 if this
%  function is to be used.
%
%Output and Input:
%  sigvar (RxRadarSigT): The read signals.
%  antenna (AntDefT): The used antenna definition. It must be of antenna
%    type 'expAnt'. See function "defant".
%  signalFileName (StringT): Name of file which contains measured signals.
%    It normally ends with ".dbs".
%  measIndex [D](IndexT): Chooses which (1.. max) of several measurement
%    in the signal file to use. Several measurements can be specified, in
%    which case they are stored as different trials (trialIx) in the output 
%    signal. Default is to use the first measurement only.
%    "measIndex" cannot be used for measurements in active mode (radar mode).
%  snapshots [D](IndexT): Which snapshots to use. This input variable allows
%    for dividing long signals into shorter ones. The available range of
%    snapshots is equal to the number of rows of the matrix "vfilt", seen
%    by "matwhos file.dbs", where "file.dbs" is the antenna signal file.
%  dbName [D](StringT): Name of measurement database including full search path.
%    Not implemented.
%  measName [D](StringT): Name of measurement. Not implemented.
%  pModulation (CxVectorT): The complex coefficients for the  modulation
%    code (see function "getmod"). For radar measurements this parameter
%    should be specified if pulse compression etc. is to work. For passive
%    mode, this input parameter is not needed.
%
%Global Variables:
%  c0 (RealScalarT) [from defant]: The speed of light in vacuum.
%
%--------
%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:
%  ant = defant('expAnt');
%  setcal1('wctab','dbtex.dbc')
%  sig = expsig1(ant,'dbtex.dbs',1, 65:128);
%  R = ecorrm(sig);
%  spect2 = sdoaspc('capon',R,d2r(-30:0.25:30));
%  spect3 = sdoaspc('cbf',sig,d2r(-30:0.25:30));
%  splot2(spect2, '',spect3)
%  pdoapar(sdoapar1('dml',sig, doaStart))
%
%Software Quality:
%  (About what is done to ascertain software quality. What tests are done.)
%  This function with dbs-files of version 2 was used in the work done by
%  A. Heydarkhan [4].
%
%Known Bugs:
%  If the input parameter "pModulation" is not specified for radar measurements,
%  no pulse modulation is stored in the output signal. This information can
%  be acquired from the measurement database but currently not from the DBS 
%  file. If performing for example pulse compression on the output signal, 
%  the field "sigvar.waveform.pModulation" in the output signal "sigvar"
%  must first be set manually. This must also be done if a modulation different
%  from the transmitted, e.g. a measured, is to be used for pulse compression 
%  etc.
%
%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.
%  [2]: Pettersson L., Danestig M., Sj鰏tr鰉 U.: "An Experimental S-Band
%    Digital Beamforming Antenna", IEEE AES Systems Magazine, November 1997,
%    p.19-26.
%  [3]: Bj鰎klund S.:"A MATLAB Toolbox for Radar Signal Processing",
%    Proceedings of Nordic MATLAB Conference `97, Stockholm 27-28 October 1997.
%  [4]: Heydarkhan A.: "Model Based Direction of Arrival Estimation Methods
%    Applied to Experimental Antenna Data", Master's Thesis, Chalmers
%    University of Technology 1997. FOA-R--97-00631-408--SE, FOA November 1997.
%
%See Also:
%  defant, setcal1, compsim2, ecorrm, doaspc1, doapar1, dbtex7

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%  Start        : 970609 Svante Bj鰎klund (svabj).
%  Latest change: $Date: 2000/11/17 12:45:24 $ $Author: svabj $.
%  $Revision: 1.37 $
% *****************************************************************************

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

if (nargin < 2)
  dbterror('To few input parameters.')
end

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

if (nargin < 3)
  measIndex = [];
end
if (nargin < 4)
  snapshots = [];
end
if (nargin < 5)
  dbName = [];
end
if (nargin < 6)
  measName = [];
end
if (nargin < 7)
  pModulation = [];
end


% ****************** Default values ******************
if isempty(measIndex)
  measIndex = 1;
end%if
if isempty(snapshots)
  %This is done below.
end%if
if isempty(pModulation)
  pModulation = [];
    % What should it be? Is the modulation known?
    % Can it be fetched from the DBS file?
end%if


% ****************** Error check input parameters ******************
chkdtype(antenna, 'AntDefT')
chkdtype(signalFileName, 'StringT')
chkdtype(measIndex, 'IntScalarT','IndexT')
chkdtype(snapshots, 'IndexT','EmptyT')
chkdtype(pModulation, 'CxVectorT','EmptyT')


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

% ----------------------------------------------------------------------- %
% Do the work.
% ----------------------------------------------------------------------- %
if ~isfield(antenna,'name')
  dbterror('Not implemented for the specified antenna type.')
else
  if ~(strcmp(antenna.name,'expAnt'))
    dbterror('Not implemented for the specified antenna type.')
  else
    extraIx = [];
    cpiIx   = [];
    trialIx = [];

    global c0 % From defant.
    exp2dbtversion =  matgetm(signalFileName,'exp2dbtversion');
    %fprintf('expsig1:exp2dbtversion=%d\n',exp2dbtversion)
    if (exp2dbtversion >= 3)
      Ipri = matgetm(signalFileName,'Ipri');
    else
      Ipri = 1;
    end;
    noPri = length(Ipri);
      % The words "PRI" and "pulse" are the same.

    vfilt = matgetm(signalFileName,'vfilt');
    if isempty(snapshots)
      snapshots = (1:size(vfilt,1));
    end%if
    noSnapshots = length(snapshots);
    noElem = antenna.noElem;
    fRFMHz  = matgetm(signalFileName,'fRFMHz'); % Carrier frequency.
    fsigMHz = matgetm(signalFileName,'fsigMHz');  % Signal frequency.
    lambda = c0/((fRFMHz+fsigMHz)*1e6); % The right value of the wavelength.
    downConversion = 4;
    sampleTime = downConversion/(25.8e6);

    % ------------------------------------------------------------------- %
    %  Passive mode.
    % ------------------------------------------------------------------- %
    if (noPri == 1)
      if ~((exp2dbtversion == 2) | (exp2dbtversion == 3))
        dbterror('Wrong version of the file ',signalFileName)
      else
        noMeasIx = length(measIndex);
        signals = zerosm([noSnapshots 1 noElem 1 1 noMeasIx]);
          % Only one range bin and CPI in passive mode.
        for trialIxLoop = 1:noMeasIx
          oneMeasIndex = measIndex(trialIxLoop);
          X = (vfilt(snapshots,(oneMeasIndex-1)*noElem + [1:noElem])).';
            % X(m,n), where m is index for elements and n index for snapshots .
          signals = setm(signals, X.', ':',1,':',1,1, trialIxLoop);
          dbtloopinfo('expsig1', [], ':', noSnapshots, 1, 1, ':',noElem, ...
            1, 1, 1, 1,trialIxLoop, noMeasIx)
        end%for trialIxLoop
        dbtinfo('');	%New line.
        waveform = defwave(lambda,1,noSnapshots,[],sampleTime);
        pulIx = 1:noSnapshots;
        ranIx = 1;
        spaIx = 1:noElem;
        trialIx = measIndex;
      end%if exp2dbtversion

    % ------------------------------------------------------------------- %
    %  Active mode.
    % ------------------------------------------------------------------- %
    else % (noPri > 1)
      if ~(exp2dbtversion == 3)
        dbterror('Wrong version of the file ',signalFileName)
      else
        if (measIndex ~= 1)
          dbterror('Index <> 1 cannot be used in active mode.')
        end%if
        if isempty(pModulation)
          dbterror(['The input parameter "pModulation" must be specified ',...
            'in active (radar) mode.'])
        end%if

        signals = zerosm([noPri noSnapshots noElem 1 1]);
          % Only one trial is implemented.
        for npri = Ipri   % Loop over all values in the vector Ipri.
          % X = (vfilt(snapshots,(npri-1)*noElem + [1:noElem])).';
          signals(npri,':',':',1,1) = (vfilt(snapshots,(npri-1)*noElem + ...
            noPri*(measIndex-1) + [1:noElem]));
            % X(m,n), where m is index for elements and n index for snapshots .
          %--signals = setm(signals, X.', npri,':',':',1,1);
          %signals(npri,':',':',1,1) = X.';  % setm
            % Test of change to Matlab 5 indexing instead of setm:
            %>> all(all(all((sig.signals == sig12.signals),1),2),3)
            %  ans =
            %        1
          infoStr = sprintf('expsig1: npri = %d(%d)\r',npri,length(Ipri));
          dbtinfo(infoStr,1);
        end%for npri
        dbtinfo('');	%New line
        if (~isempty(dbName) & (~isempty(measName)))
          disp('Reading measurement information from measurement database...')
          angedb(dbName)
          angemat(measName)
	  noRangeBinsTot = round(mparam('Kpri') * (1/3.225e6)/sampleTime);
   	    % Is this correct? The intended in defwave?
        else
	  noRangeBinsTot = noSnapshots;  % Better than nothing.
	end%if
        waveform = defwave(lambda,noRangeBinsTot,noPri,pModulation,sampleTime);
        pulIx = 1:noPri;
        ranIx = 1:noSnapshots;
        spaIx = 1:noElem;
      end%if exp2dbtversion
    end%if noPri

    % ------------------------------------------------------------------- %
    %  Finnish. Create ouput variable.
    % ------------------------------------------------------------------- %
    sigvar = RxRadarSigT(signals,{antenna,waveform},[], pulIx,ranIx,spaIx, ...
      extraIx,cpiIx,trialIx);
  end%if expAnt
end%if name