function signal = additive(num_samples, frequency, freq_skew, ...		amplitude, freq_env, amp_env, partials, Fs)%ADDITIVE Additive synthesis algorithm%   ADDITIVE(NUM_SAMPLES, FREQUENCY, FREQ_SKEW, AMPLITUDE, FREQ_ENV, AMP_ENV,%   PARTIALS, FS) synthesizes a signal using separate envelopes for FREQUENCY%   and AMPLITUDE of a single sinusoid for NUM_SAMPLES. The sinusoid's%   FREQUENCY is scaled by FREQ_ENV (between 0 - 1) proportional to FREQ_SKEW.%   AMPLITUDE remains in the domain 0 - 1, even when scaled by AMP_ENV.%%   Example: %   Todo: employ varargin%%   Author(s): Bob L. Sturm, 20030701-03%   Copyright 2003 University of California, Santa Barbara%   $Revision: 1.20 $  $Date: 2002/03/28 17:31:26 $	partials = partials{:};	num_partials = size(partials,2)/2;	% Create envelopes	freq_envelope = zeros(1,num_samples);	amp_envelope = zeros(1,num_samples);	% Populate envelopes	segment = [0 0];	value = [0 0];	amp_env = amp_env{:};	for i=1:length(amp_env)/2-1,		segment(1) = floor(amp_env(2*i-1)*num_samples+1);		% Start		segment(2) = floor(amp_env(2*i+1)*num_samples);		% End		value(1) = amp_env(2*i);		value(2) = amp_env(2*(i+1));		amp_envelope(segment(1):segment(2)) = amplitude*...			linspace(value(1),value(2),segment(2)-segment(1)+1);	end	%figure	%plot(linspace(0,1,num_samples),amp_envelope);	segment = [0 0];	value = [0 0];	freq_env = freq_env{:};	for i=1:length(freq_env)/2-1,		segment(1) = floor(freq_env(2*i-1)*num_samples+1);		% Start		segment(2) = floor(freq_env(2*i+1)*num_samples);		% End		value(1) = freq_env(2*i)*freq_skew;		value(2) = freq_env(2*(i+1))*freq_skew;		freq_envelope(segment(1):segment(2)) = ...			linspace(value(1),value(2),segment(2)-segment(1)+1);	end	%figure	%plot(linspace(0,1,num_samples),freq_envelope)	% Create signal	signal = zeros(1,num_samples);	for i=1:num_partials,		freq(i) = 0;	end	for i=1:num_samples,		for j=1:num_partials,			% Integrate frequency function			freq(j) = freq(j) + (freq_envelope(i)+frequency*partials(2*j-1))/Fs;			signal(i) = signal(i) + ...				partials(2*j)*amp_envelope(i).*sin(2*pi*freq(j));		end	end% HISTORY% Modified from original Common Lisp Music (CLM) code, from CCRMA, Stanford.%(definstrument bird %	(startime dur frequency freq-skew amplitude freq-envelope amp-envelope)%	(multiple-value-bind (beg end) (times->samples startime dur)%		(let* ((amp-env (make-env amp-envelope amplitude dur))%			(gls-env (make-env freq-envelope (hz->radians freq-skew) dur))%			(s (make-oscil :frequency frequency)))%			(run (loop for i from beg to end do%				(* (env amp-env) (oscil s (env gls-env))))))))%% So this defines an instrument (function) called bird which takes as required% arguments:% 			startime, dur, frequency, freq-skew, %			amplitude, freq-envelope, amp-envelope,%(definstrument bigbird %	(start dur frequency freqskew amplitude freq-envelope amp-envelope partials)%	(multiple-value-bind (beg end) (times->samples start dur)%		(let* ((gls-env (make-env freq-envelope (hz->radians freqskew) dur))%			(os (make-oscil :frequency frequency))%			(coeffs (partials->polynomial (normalize-partials partials)))%			(amp-env (make-env amp-envelope amplitude dur)))%			(run (loop for i from beg to end do%				(* (env amp-env) (polynomial coeffs (oscil os (env gls-env)))))))))% So this defines another instrument called bigbird which takes as required% arguments:% 			startime, dur, frequency, freq-skew, %			amplitude, freq-envelope, amp-envelope, partials,