Comments and Remarks over Classic Linear Loop-Gain Method for Oscillator Design and Analysis. New Proposed Method Based on NDF/RRT Articles uri icon

publication date

  • April 2012

start page

  • 478

end page

  • 491


  • 1


  • 21

International Standard Serial Number (ISSN)

  • 1210-2512


  • This paper describes a new and original method for designing oscillators based on the Normalized Determi- nant Function (NDF) and Return Relations (RR T ). Firstly, a review of the loop-gain method will be performed. The loop-gain method pros, cons and some examples for explor- ing wrong solutions provided by this method will be shown. This method produces in some cases wrong solutions be- cause some necessary conditions have not been fulfilled. The required necessary conditions to assure a right solution will be described. The necessity of using the NDF or the Transpose Return Relations (RR T ), which are related with the True Loop-Gain, to test the additional conditions will be demonstrated. To conclude this paper, the steps for os- cillator design and analysis, using the proposed NDF/RR T method, will be presented. The loop-gain wrong solutions will be compared with the NDF/RR T and the accuracy of this method to estimate the oscillation frequency and Q L will be demonstrated. Some additional examples of plane refer- ence oscillators (Z/Y / G ), will be added and they will be an- alyzed with the new NDF/RR T proposed method, even these oscillators cannot be analyzed using the classic loop gain method


  • oscillator; normalized determinant function; ndf; stability; loop-gain