程序各部分都是什么意思

[winnertnt]

clf
close all
hf = figure ( ’position’, [ 313, 79, 250, 443 ] ) ;
num = str2num ( get ( handles. fenzi, ’string’) ) ;
den = str2num ( get ( handles. fenmu, ’string’) ) ;
w = str2num ( get ( handles. ww, ’string’) ) ;
GW = polyval ( num, j3 w). /polyval ( den, j3 w)
AW = abs (GW)
phy = angle (GW)
set ( handles. tx, ’string’, GW)
set ( handles. fp, ’’string’,AW)
set ( handles. xp, ’string’, phy)
G = tf ( num, den) ;
bode (G) ;
麻烦高手给解释下每条语句都是做什么用得