consider a system in its Fourier transform form:

1+j
(1+j

in control textbooks, the bode plot is draw like this: the amplitude is the same in the bode plot, while the first system's phase curve is within 0 to -90. Due to nonmininmum phase characteristics of the nonminimum phase sytem, the phase curve is 0 to -180. However the Matlab always draw the nonminimum phase sytem's phase curve within 180 to 0. Why? we all know that nonmininmum phase system contains a large scale of the phase lag, why does Matlab use this kind of fashion?

1+j

***w***T/ (1+j***w***T1) and its nonminimum phase counterpart: 1-j***w***T/***w***T1) where 0<T<T1in control textbooks, the bode plot is draw like this: the amplitude is the same in the bode plot, while the first system's phase curve is within 0 to -90. Due to nonmininmum phase characteristics of the nonminimum phase sytem, the phase curve is 0 to -180. However the Matlab always draw the nonminimum phase sytem's phase curve within 180 to 0. Why? we all know that nonmininmum phase system contains a large scale of the phase lag, why does Matlab use this kind of fashion?