This article presents a selection of the calculated and measured results of an oscillator circuit using two source-coupled junction field-effect transistors (JFETs), which are investigated at a number of different operating points. These results illustrate vividly some strange but typical problems of the oscillator design, such as “spurious” and “wrong” or “jumping” oscillation frequency. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 550–563, 2004.

An improved CAD procedure for oscillator circuit design using fast-approximation formulas describing the voltage-dependent non-linear characteristics of the intrinsic equivalent circuit elements of the active devices: Research Articles

This article has shed some light upon typical problems of the oscillator design. A number of additional signals can be excited by the oscillator's active kernel due to parasitic effects. These interfere with the projected oscillation frequency or with its harmonics and produce a number of disturbing spurious signals. By the help of a suitable CAD program, such as C/NL2, it is possible to avoid this problem. The CAD program can analyze the reason for these additional oscillations and comfortably give advice how to take measures to inhibit the oscillator's circuit capability to produce these unwanted additional parasitic oscillations. This article examined the problem of exciting spurious emission in an oscillator circuit and proves, that an oscillator can be easily CAD designed and assembled, producing the designed frequency signal, only

Oscillator design for suppressing spurious signals

The non-linear characteristics of the intrinsic transistorpsilas equivalent circuit elements are determined by S-parameter measurements at a large number of different operating points and then approximated by fast computable formulas. These equations can be inserted into a suitable CAD program in order to perform a successful non-linear circuit design, such as e.g. developing oscillator and mixer circuits.

Fast approximation formulas describing the non-linear intrinsic transistor equivalent circuit elements

C/NL2 for windows: Linear and nonlinear microwave circuit analysis and optimization, by Stephen A. Maas and Arthur Nichols, Nonlinear Consulting, P.O. Box 7284, Long Beach, CA 90807, USA. Tel/Fax: 310‐426‐1639

Norbert H. L. Koster

Papers

C/NL2 for windows: Linear and nonlinear microwave circuit analysis and optimization, by Stephen A. Maas and Arthur Nichols, Nonlinear Consulting, P.O. Box 7284, Long Beach, CA 90807, USA. Tel/Fax: 310‐426‐1639