function ptfd(tfd, t, f, fs)% ptfd -- Display an image plot of a TFD with a linear amplitude scale.%%  Usage%    ptfd(tfd, t, f, fs)%%  Inputs%    tfd  time-frequency distribution%    t    vector of sampling times (optional)%    f    vector of frequency values (optional)%    fs   font size of axis labels (optional)% Copyright (C) -- see DiscreteTFDs/Copyrighterror(nargchk(1, 4, nargin));if (nargin < 4)  fs = 10;endif (nargin < 3)  f = [-0.5 0.5];endif (nargin < 2)  t = [1 size(tfd,2)];endif isempty(t)  t = [1 size(tfd,2)];endif isempty(f)  f = [-0.5 0.5];endimagesc(t, f, abs(tfd)), axis('xy'), xlabel('time','FontSize',fs), ylabel('frequency','FontSize',fs), set(gca,'FontSize',fs);