Implementing Harmonic Balance

This chapter describes practical algorithms for implementing harmonic balance. Most of these algorithms have been implemented and tested in Spectre, a simulation program suitable for analog and microwave circuits. There are two fundamental ideas presented in this chapter. The first is that it is possible to use the DFT with harmonic balance, even when the signals present are not periodic. The benefit of the DFT is the very regular manner in which aliasing occurs, which can be exploited to accelerate the construction and factorization of the conversion matrices. The first portion of this chapter is dedicated to explaining how the DFT can be used in quasiperiodic harmonic balance, and rederiving harmonic Newton with the DFT.