If the enclosed ‘s’ plane closed route is made up of only poles, then the direction of the encirclement within the $G(s)H(s)$ aircraft will be reverse to your course from the enclosed closed route from the ‘s’ aircraft. There are 2 indication alterations in the 1st column of Routh table. https://cncmachineforsale09755.prublogger.com/13731837/helping-the-others-realize-the-advantages-of-control-system