@TechReport{	  it:2003-036,
  author	= {Emad Abd-Elrady and Torsten S{\"o}derstr{\"o}m and
		  Torbj{\"o}rn Wigren},
  title		= {Periodic Signal Modeling Based on Li{\'e}nard's Equation},
  institution	= {Department of Information Technology, Uppsala University},
  department	= {Division of Systems and Control},
  year		= {2003},
  number	= {2003-036},
  month		= aug,
  abstract	= {The problem of modeling periodic signals is considered.
		  The approach taken here is motivated by the well known
		  theoretical results on the existence of periodic orbits for
		  Li{\'e}nard systems and previous results on modeling
		  periodic signals by means of second order nonlinear
		  ordinary differential equations (ODEs). The approach makes
		  use of the appropriate conditions imposed on the
		  polynomials of a Li{\'e}nard system to guarantee the
		  existence of a unique and stable limit cycle. These
		  conditions reduce the number of parameters required to
		  generate accurate models for periodic signals.}
}