chart — Nichols chart
chart([flags]) chart(gain [,flags]) chart(gain,phase [,flags])
real vector ( gains (in DB))
real vector (phases (in degree))
a list of at most 4 flags list(sup [,leg [,cm [,cphi]]])
1 indicates superposition on the previous plot 0 no superposition is done
1 indicates that legends are drawn, o: no legends
color index for gain curves
color index for phase curves
plot the Nichols'chart: iso-gain and iso-phase contour of y/(1+y) in phase/gain plane
chart
may be used in cunjunction with
black.
The default values for gain
and
phase
are respectively :
[-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]
[-(1:10) , -(20:10:160)]
s=poly(0,'s') h=syslin('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01)) black(h,0.01,100) chart(list(1,0,2,3)); clf() h1=h*syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225)) black([h1;h],0.01,100,['h1';'h']) set(gca(),'data_bounds',[-180 -30;180 30]) //enlarge the frame chart(list(1,0));