Title :
Finding phase margin of feedback systems from closed loop AC simulations
Author :
Ochoa, Agustin, Jr. ; Tang, Howard
Author_Institution :
Xtreme Spectrum, Inc, Greenbelt, MD, USA
Abstract :
The stability of a feedback system is generally characterized with a point variable, the system phase margin. Phase Margin is a function of the system loop gain and is not always well defined. In this paper we show how to obtain the phase margin from the closed loop system response by translating the phase of this function with a simple algebraic relation. As the method utilizes a closed loop result and an exact algebraic translation, the results fully account for all loading and effects of feed-forward through the feedback and any reverse transmission through the active elements
Keywords :
analogue circuits; circuit feedback; circuit stability; linear network analysis; signal flow graphs; transfer functions; SFG; algebraic translation; closed loop AC simulations; closed loop system response; closed loop transfer functions; feedback system stability; feedforward; linear circuits; point variable; signal flow graphs; system loop gain; system phase margin; Circuit stability; Circuit topology; Closed loop systems; Feedback circuits; Feedback loop; Flow graphs; Frequency estimation; Impedance; Phase measurement; Transfer functions;
Conference_Titel :
Circuits and Systems, 2000. Proceedings of the 43rd IEEE Midwest Symposium on
Conference_Location :
Lansing, MI
Print_ISBN :
0-7803-6475-9
DOI :
10.1109/MWSCAS.2000.951436
