estlocalfreq.m

阵列信号处理的工具箱

function freqEst = estlocalfreq(sigVec,fSamp)

%ESTLOCALFREQ Estimates the local (instantaneous) frequency of an complex signal vector.
%
%--------
%Synopsis:
%  freqEst = estlocalfreq(sigVec,fSamp)
%
%Description:
%  Estimates the local (instantaneous) frequency of an complex signal vector.
%
%Output and Input:
%  freqEst (RealVectorT): Local frequency estimate [Hz].
%  sigVec (RealVectorT): Input complex signal vector.
%  fSamp (RealScalarT): Sampling frequency for "sigVec".
%
%--------
%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:
%  len = 1024;		% Number of samples.
%  maxFDev = 500;	% Maximum frequency deviation [Hz].
%  fSamp = 2000;		% Sampling frequency [Hz].
%  Ts = 1/fSamp;		% Sampling time [s].
%  t = linspace(0, Ts*len, len);
%  codeCalc = getmod('chirp',[maxFDev,fSamp,len]);
%  freqEst = estlocalfreq(codeCalc, fSamp);
%  figure, plot(t,[0;freqEst])
%  title('Frequency estimation')
%  xlabel('Time [s]')
%  ylabel('Frequency [Hz]')
%
%Software Quality:
%  (About what is done to ascertain software quality. What tests are done.)
%
%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:
%  getmod tdbt(101)

%   *  DBT, A Matlab Toolbox for Radar Signal Processing  *
% (c) FOA 1994-2000. See the file dbtright.m for copyright notice.
%
%  Start        : 980710 Svante Bj鰎klund (svabj).
%  Latest change: $Date: 2000/10/16 15:20:53 $ $Author: svabj $.
%  $Revision: 1.3 $
% *****************************************************************************

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

if (nargin < 2)
  error('DBT-Error: To few input parameters.')
end

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

%arginNo=2;
%if (nargin < arginNo)
%  mainPointDoa = [];
%end
%arginNo = arginNo +1;

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

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

%if isempty(lambda)
%  lambda = 1;
%end%if

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


% ----------------------------------------------------------------------- %
% Calculate the antenna pattern.
% ----------------------------------------------------------------------- %

freqEst = 1/(2*pi) * diff(unwrap(angle(sigVec))) * fSamp;	% [Hz]