White Paper: Rate Harmonic Balance Provides A New Solution For Nonlinear Simulation

By Ville Karanko and Taisto Tinttunen, AWR Corporation/APLAC Division

Since the early 1980s, harmonic balance analysis has been the core tool for performing nonlinear frequency- domain simulation. Today's harmonic balance tools such as AWR's APLAC® simulator can handle designs with thousands of analysis frequencies and scale almost linearly with increases in circuit elements, nodes, and frequencies. However, when applied to large circuits that have many different signal sources, traditional harmonic balance has drawbacks that render it less effective because computational times are prohibitively long and enormous amounts of memory are required. To this end, AWR has introduced within its APLAC family of harmonic balance and time-domain simulators a technology called Multi-Rate Harmonic Balance (MRHB™). This new technology eliminates the limitations of traditional harmonic balance, dramatically increasing computational speed and reducing required computer memory when analyzing frequency-rich nonlinear systems that have multiple signal sources. It can potentially even solve entire subsystems such as a mobile phone transceiver in an acceptable amount of time.

Traditional harmonic balance analysis is struggling to keep pace with the industry's need to solve large and larger high-frequency circuits. However, the intelligent frequency selectivity and other techniques within MRHB bring new life to harmonic balance and make it ready to tackle the challenges these circuits present. AWR has applied for a patent covering MRHB, which has been in development for several years. It is now a core component of AWR's APLAC simulator portfolio and is available within AWR's Design Environment Version 2009.