output volt- age. These components are respectively obtained by means of averaging and via analysis of SPICE-like simulation results. In a final step, we construct a behavioral model for the oscillator's transient behavior. This model implements the averaged equations (5.179) and (5.180). The right-hand sides ha (A) and he(A) are stored as a table of 31 precomputed values. We evaluate them by means of table lookup and linear interpolation. Computing the 31 values requires 3 minutes of CPU time. Fig. 5.32 compares the oscillator startup behavior predicted by the behavioral model, which directly computes the oscillation amplitude, with the solution of the original circuit equations. The latter was obtained using a SPICE-like algorithm.As can be seen, there is excellent agreement (to within 1%) between the SPICE-like simulation results and the amplitude envelope predicted by the behavioral model. As far as computational complexity is concerned, we observe that simulations based on the behavioral model only take 0.4 seconds to complete. Solving of the exact circuit equations takes 37.2 seconds. These numbers hold for simulations ranging over 20 pe- riods of oscillation. The results demonstrate a significant simulation speedup whereby the behavioral model is solved up to a 100 times faster. The reasons for this speedup are twofold. Firstly, the behavioral model can be solved using a much larger time step. It "skips" fast-varying oscillations and directly computes amplitude and phase behavior. The speedup mentioned above doesn't seem like a big deal. For a designer, there is little difference in having to wait 1 or 30 seconds. But the simulations above ran over a very limited simulation time span, covering only 20 periods of oscillation. Fig. 5.33 plots the simulation (CPU) time as a function of the simulation time span relative to the oscillation period. This is done for both SPICE-like transient simulations and for sim- ulations performed with the model extracted by means of the methods here developed. As is observed