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// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA Serge Steer
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
function chart(attenu,angl,flags)
titre=_("Amplitude and phase contours of y/(1+y)")
l10=log(10);
ratio=%pi/180;
defaultAngles = [1:10,20:10:160];
//
[lhs,rhs]=argn(0)
select rhs
case 3 then
case 2 then,
if type(angl)==15 then
// angl actually stands for flags
flags=angl
angl = defaultAngles;
else
// angl is the phase
flags=[]
end
case 1 then
if type(attenu)==15 then
flags=attenu
attenu=[-12 -8 -6 -5 -4 -3 -2 -1.4 -1 -.5 ,..
0.25 0.5 0.7 1 1.4 2 2.3 3 4 5 6 8 12];
else
flags=list()
end
angl = defaultAngles;
else
flags=list()
attenu=[-12 -8 -6 -5 -4 -3 -2 -1.4 -1 -.5 ,..
0.25 0.5 0.7 1 1.4 2 2.3 3 4 5 6 8 12];
angl = defaultAngles;
end
// convert angles to radian
angl = -angl * ratio;
c1=color('lightgrey');c2=c1
select size(flags)
case 0 then
flags=list(0,-1,c1,c2)
case 1 then
flags=list(flags(1),-1,c1,c2)
case 2 then
flags=list(flags(1),flags(2),c1,c2)
case 3 then
flags(4)=c2
end
//
if ~flags(1) then
clf()
ax=gca();
ax.data_bounds=[-360,-50;0,40];
ax.axes_visible='on';
ax.box='on';
ax.tight_limits='on'
else
ax=gca();
end
ax.clip_state="clipgrf"
// ax.data_bounds=[0,-50;360,40];
phi_min=ax.data_bounds(1,1)
phi_max=ax.data_bounds(2,1)
k1=floor(phi_min/180)
k2=ceil(phi_max/180)
//
drawlater()
if flags(2) then xtitle(titre,_("phase(y) (degree)"),_("magnitude(y) (Db)")),end
llrect=xstringl(0,0,'1')
//isogain curves
lambda=exp(l10*attenu/20)
rayon=lambda./(lambda.*lambda-ones(lambda))
centre=-lambda.*rayon
//
if attenu<>[]
for i = 1:prod(size(attenu)),
att=attenu(i);
if att<0 then
w=%eps:0.03:%pi;
else
w=-%pi:0.03:0;
end;
n=prod(size(w))
rf=centre(i)*ones(w)+rayon(i)*exp(%i*w);
phi=atan(imag(rf),real(rf))/ratio; //phi is in [-180 0]
module=20*log(abs(rf))/l10;
//use symetry and period to extend the curve on [k1*180 k2*180]
p=[];m=[];
S=[]
for k=k1:k2-1
if pmodulo(k,2)==0 then
p=[p %nan k*180-phi($:-1:1)]
m=[m %nan module($:-1:1)]
if att>0 then
xstring(p($),m($),string(att),0,0),
e=gce();
if ~flags(1) then e.clip_state='off';end
S=[e S]
end
else
p=[p %nan ((k+1)*180)+phi]
m=[m %nan module]
if att<0 then
xstring(p($),m($),string(att),0,0),
e=gce();
if ~flags(1) then e.clip_state='off';end
S=[e S]
end
end
end
xpoly(p,m)
e=gce();e.foreground=flags(3);//e.line_style=3,
if size(S,'*')>1 then S=glue(S),end
S=glue([S,e]);S.user_data=att;
end;
glue(ax.children(size(attenu,'*'):-1:1))
end
//isophase curves
if angl<>[] then
eps=100*%eps;
for teta=angl,
if teta < -%pi/2 then
last=teta-eps,
else
last=teta+eps,
end;
w=[-170*ratio:0.03:last last]
n=prod(size(w));
module=real(20*log((sin(w)*cos(teta)/sin(teta)-cos(w)))/l10)
w=w/ratio
p=[];m=[];
for k=k1:k2-1
if pmodulo(k,2)==0 then
p=[p %nan k*180-w($:-1:1)]
m=[m %nan module($:-1:1)]
else
p=[p %nan ((k+1)*180)+w]
m=[m %nan module]
end
end
xpoly(p,m)
e=gce();e.foreground=flags(3);//e.line_style=3,
e.user_data=teta
end;
glue(ax.children(size(angl,'*'):-1:1))
end
drawnow() ;
endfunction
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