function outsig = sig_bandpassnoise(fc,fs,dur,l,bw)
%sig_bandpassnoise  Generates a bandpass-noise-type masker
%
%   Usage:   outsig = sig_bandpassnoise(fc,fs,dur,l,bw)
%
%   Input parameters:
%       fc:     center frequency of the bandpass
%       fs:     sampling frequency
%       dur:    duration of the bandpassnoise in s
%       l:      overall level in (db SPL) with a dB-offset of 0 dB
%       bw:     bandwidth of the noiseband
%
%   Output parameters:
%       outsig: the generated bandpassnoise
%
%   outsig = SIG_BANDPASSNOISE(fc,fs,dur,l,bw) generates a bandpass-noise
%   masker with duration dur (in sec), overall level l (in dB SPL) and
%   with a sampling rate of fs Hz at the center frequency fc. The 
%   bandpass has a bandwidth of bw in Hz. The generation is in the
%   frequency domain.
%
%   Author:     Martina Kreuzbichler
%
%   Url: http://amtoolbox.org/amt-1.1.0/doc/signals/sig_bandpassnoise.php

% Copyright (C) 2009-2021 Piotr Majdak, Clara Hollomey, and the AMT team.
% This file is part of Auditory Modeling Toolbox (AMT) version 1.1.0
%
% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program.  If not, see <http://www.gnu.org/licenses/>.

if nargin<5
  error('%s: Too few input parameters.',upper(mfilename));
end;


% Make sure the length is even
n = round(dur*fs/2)*2;

% Caluculation of variables
fl = fc-bw/2;
fh = fc+bw/2;
resolution = fs/n;
flpin = round(fl/resolution);
fhpin = round(fh/resolution);

%special case when bandwidth is twice the centerfrequency
if flpin == 0
    flpin = 1;
end




%% Generate broadband Gaussian noise

% Make sure the length is even
n = round(dur*fs/2)*2;

%% Generation in the frequency domain
a = zeros(n/2+1,1);
a_dB = a;
inds = flpin:fhpin;
a_dB(inds) = 1;
a(inds) = 10.^(a_dB(inds)/20)*sqrt(n)/2;
p = randn(n/2+1,1) + 1i*randn(n/2+1,1);
sig = bsxfun(@times,a,p);
noisebp = ifftreal(sig,n);
outsig = scaletodbspl(noisebp,l,'dboffset',0);  
 

%% Plot results (uncomment if needed)

% fax = 0:resolution:fs-resolution;
% plot(fax, abs(fft(noisebplv)))