chart

Nichols chart

Calling Sequence

chart([flags])
chart(gain [,flags])
chart(gain,phase [,flags])

Arguments

:gain real vector ( gains (in DB)) : :phase real vector (phases (in degree)) : :flags a list of at most 4 flags list(sup [,leg [,cm [,cphi]]])

:sup 1 indicates superposition on the previous plot 0 no superposition

is done

: :leg 1 indicates that legends are drawn, o: no legends : :cm color index for gain curves : :cphi color index for phase curves :

:

Description

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)]

Examples

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));

See Also

• nyquist nyquist plot
• black Black-Nichols diagram of a linear dynamical system