Post date: Apr 10, 2014 12:43:37 AM
Yes, of course!
Non-minimum phase (NMP) systems appear either when a NMP element (such as transport lag) is present in the system or may be when an inner loop is unstable.
One can draw Bode plot for NMP systems, but the magnitude and phase-angle plots are not 'uniquely related'. For a MP system, the magnitude and phase-angle plots are uniquely related, meaning that if either one of them is specified over the entire frequency range, the other plot can be determined uniquely. This does not apply to NMP systems.
Also, it is possible to detect whether a system is MP or NMP by looking at the Bode plot at high frequency asymptotes. If at high frequency, the phase angle is -90*r, where r is the difference in the degrees of denominator and numerator, then the system is MP. Both MP and NMP systems will have a slope of -20*r dB/decade at high frequency.