RF Electronics Chapter 2: Computer Simulation Page 34
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
done using linear simulation models and then the final design is optimised using the
harmonic balance models. HB simulation produces steady state results only.
Figure 2.41. Harmonic Balance option windows.
Harmonic balance simulation can be carried out by simply changing the properties of the
measurements of the voltage transient analysis graph from APLAC Trans to APLAC HB,
as shown on the left of figure 2.41. Since the input waveform is a square wave, the number
of tone harmonics to be used needs to increase. Select Options Default Circuit Options
Harmonic Balance, and then increase the number of harmonics to 32 as shown in as
shown on the right of figure 2.41.
Figure 2.42. Waveforms for the circuit of figure 2.43 using Harmonic Balance.
Figure 2.42 shows the voltage waveform resulting from the Harmonic Balance
simulation, using 32 harmonics. The time scale corresponds to 2 steady-state cycles of
the input waveform. The output voltage level is slightly higher than the one obtained
using the time domain simulation, as shown in figure 2.36. Having a lower number of
harmonics results in a more distorted square waveform and a higher output voltage. The
convergence depends on the number of harmonics and the waveform duty cycle. The
RF Electronics: Design and Simulation
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