y with which the framework here de- veloped allows us to handle complex nonlinear phenomena. With regard to oscillator phase noise, the theory here presented embeds existing work [Dem98, Dem00a] in a more global framework. Moreover, this work has resulted in a semi-analytic method to compute an oscillator's phase noise spectrum, including the details close to the os- cillation frequency [Vana03c]. With regard to the behavioral modeling of harmonic oscillators, we obtained model equations that can be solved with a simulation time step that is much larger than would be possible for the (SPICE-like) solution of the original set of circuit equations. They were proven accurate and fast for both a single harmonic oscillator and a harmonic quadrature oscillator. 6.2 Leads for further work It is the nature of research that the quest for knowledge tends to generate more questions than answers. This work should therefore be considered as a starting point for new research (by new researchers) rather than an as end point with nowhere to go from here. With regard to both linear system analysis and oscillator dynamics, there are still many challenges to be addressed. In what follows, some of them are listed. In the area of linear system analysis, the topics to be explored concern both fundamen- tal theory as practical applications: As presented in this text, the HTM-based frequency-domain analysis of LPTV systems can be generalized to other classes of LTV systems. These systems then transfer information between carrier waves other than the harmonic functions 6.2 LEADS FOR FURTHER WORK in this work. Suggested directions for further research involve, for example, linear quasi-periodic time-varying systems and the use of principal component analysis for autodetecting relevant sets of carrier waves. The former is useful for heterodyne transceiver small-signal analysis while the latter can, for example, be applied to capture noise behavior in nonlinear systems. The systems to which HTM-based analysis applies, are by no means exhaus