function [y,iflaw]=fmsin(N,fnormin,fnormax,period,t0,fnorm0,pm1);%FMSIN	Signal with sinusoidal frequency modulation.%	[Y,IFLAW]=FMSIN(N,FNORMIN,FNORMAX,PERIOD,T0,FNORM0,PM1)%	generates a frequency modulation with a sinusoidal frequency.%	This sinusoidal modulation is designed such that the instantaneous%	frequency at time T0 is equal to FNORM0, and the ambiguity %	between increasing or decreasing frequency is solved by PM1.%%	N       : number of points.%	FNORMIN : smallest normalized frequency          (default: 0.05) %	FNORMAX : highest normalized frequency           (default: 0.45)%	PERIOD  : period of the sinusoidal fm            (default: N   )%	T0      : time reference for the phase           (default: N/2 )%	FNORM0  : normalized frequency at time T0        (default: 0.25)%	PM1     : frequency direction at T0 (-1 or +1)	 (default: +1  )%	Y       : signal%	IFLAW   : its instantaneous frequency law (optional).%%	Example: %	 z=fmsin(140,0.05,0.45,100,20,0.3,-1.0);plot(real(z));%%	See also FMCONST, FMLIN, FMODANY, FMHYP, FMPAR, FMPOWER.%	F. Auger, July 1995.%	Copyright (c) 1996 by CNRS (France).%%	------------------- CONFIDENTIAL PROGRAM -------------------- %	This program can not be used without the authorization of its%	author(s). For any comment or bug report, please send e-mail to %	f.auger@ieee.org if (nargin == 0), error ( 'At least 1 parameter required' ) ;elseif (nargin == 1), fnormin = 0.05; fnormax = 0.45; period = N;  t0= round(N/2); fnorm0 = 0.25; pm1=+1;elseif (nargin == 2), fnormax = 0.45; period = N;  t0 = round(N/2); fnorm0 = 0.5*(fnormin+fnormax); pm1=+1;elseif (nargin == 3), period = N; t0 = round(N/2);  fnorm0 = 0.5*(fnormin+fnormax); pm1=+1;elseif (nargin == 4), t0 = round(N/2); fnorm0 = 0.5*(fnormin+fnormax); pm1=+1;elseif (nargin == 5), fnorm0 = 0.5*(fnormin+fnormax); pm1=+1;elseif (nargin == 6), pm1= +1;elseif (nargin==7), if (abs(pm1)~=1),  error('pm1 must be equal to -1 or +1'); end;end;if (N <= 0), error ('The signal length N must be strictly positive' );elseif (abs(fnormin) > 0.5)|(abs(fnormax) > 0.5)|(abs(fnorm0) > 0.5), error ('fnormin, fnormax and fnorm0 must be between -0.5 and 0.5') ;elseif (fnormin > fnormax) error ('fnormin must be lower than fnormax');elseif (fnormin > fnorm0)|(fnorm0 > fnormax), error ('fnorm0 must be between fnormin and fnormax') ;else fnormid=0.5*(fnormax+fnormin); delta  =0.5*(fnormax-fnormin); phi=-pm1*acos((fnorm0-fnormid)/delta); time=(1:N)-t0; phase=2*pi*fnormid*time+delta*period*(sin(2*pi*time/period+phi)-sin(phi)); y = exp(j*phase).'; if (nargout==2)  iflaw=fnormid+delta*cos(2*pi*time'/period+phi); endend