A general method of feedback amplifier analysis

A new method of feedback amplifier analysis is presented. The existing approaches to analysis and design of feedback amplifiers are either based on modeling of two-port amplifier and feedback networks or on calculating the return-ratio. These two approaches produce different results for the loop gain and return-ratio, and depending on circuit topology, can significantly differ in resulting closed loop gain. The new approach is based on the calculation of the return-ratio and the exact modeling of the amplifier without feedback. Resulting expressions for the loop gain and the return ratio are equivalent. The method is algorithmic and gives the exact result for the closed-loop gain. Its application is general, straightforward, allows simple approximations and is suitable for hand analysis as well as for the computer-aided symbolic or numeric analysis. The method is verified on typical examples of negative feedback amplifiers.