# Is there an English word for the output response of a non-minimum phase system?

I've noticed in some French language control courses they have a word for the initial part of the response of a non-minimum phase system. They say it has "un départ malin". I looked up malin and it means different things in English, for example:

There are plenty of descriptions of the step response of such a system: the initial direction of the step response is opposite to the final value, it goes in the opposite direction to the long-term response,

but is there a better equivalent English word to 'malin' that people commonly use to identify the non-minimum phase system response characteristic?

I've also seen the word 'undershoot' used in this context but I'm not sure that's correct.

• Many words in French have technical meanings not shown in "ordinary" dictionaries and you have found one. Perhaps a "reverse start". Jul 3 '20 at 18:01
• In some contexts, "kickback" might be applicable. Jul 3 '20 at 18:14
• I don't know of a word, either. But it seems to be basically any system possessing RHPZ where actual behavior avoids it/them.
– jonk
Jul 3 '20 at 18:27
• it appears that the root word is mal, which means wrong ... so the phrase would be wrong start .... are you certain that the spelling is malin? Jul 3 '20 at 18:57
• "Un départ malin", a nice way to put it but I never heard of the expression before : ) Malin has several meanings but here it means evil so it could be translated as an evil start-up if it makes sense. A non-minimum phase system could indeed include a RHP zero or a pure delay for instance. With a RHPZ, like in a boost or a buck-boost converter, if the setpoint change is too fast compared to the inductor available V-s then the output first dips before going up again. Slowing down the response - choosing a lower crossover frequency - ensures system stability. Jul 3 '20 at 19:57