Based on a Fourier series analysis, an analytic interconnect model is presented which is suitable for periodic signals, such as a clock signal. In this model, the far-end time-domain waveform is approximated by the summation of several sinusoids. Closed-form solutions of the 50% delay and overshoots/undershoots are provided when the fifth and higher order harmonics are ignored. Good accuracy is observed between the model and SPICE simulations. The model is applied to resistance-capacitance-inductance interconnect trees and the computational complexity of the model is linear with the size of the tree and the model order. The tree model is shown to be an effective method to analyze clock distribution networks. The single interconnect model is also extended to coupled multi-interconnect systems to analyze crosstalk noise and a general waveform solution is obtained. It is noted that in addition to the transition time, the period of the aggressor signal also has a significant effect on the crosstalk noise.