function ptfddb(tfd, dbs, t, f, fs)% ptfddb -- Display an image plot of a TFD with a dB amplitude scale.%%  Usage%    ptfddb(tfd, dbs, t, f, fs)%%  Inputs%    tfd  time-frequency distribution%    dbs  rabge in dBs (optional, default is 25)%    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, 5, nargin));if (nargin < 5)  fs = 10;endif (nargin < 4)  f = [-0.5 0.5];endif (nargin < 3)  t = [1 size(tfd,2)];endif (nargin < 2)  dbs = 25;endif isempty(t)  t = [1 size(tfd,2)];endif isempty(f)  f = [-0.5 0.5];endtfd=tfd./sum(sum(tfd));tfd=20*log10(abs(tfd)+eps);tfd = tfd - max(max(tfd));imagesc(t, f, tfd, [-dbs 0]), axis('xy'), xlabel('time','FontSize',fs), ylabel('frequency','FontSize',fs),set(gca,'FontSize',fs);