Getting an Accurate FFT Spectral Plot in SmartSpice

Introduction

The transient simulation uses an adaptive time-stepping algorithm depending on the change in the circuit waveforms (dV/dT). This means the simulated waveform consists of uneven time steps (more time points are required round a rapidly changing voltage to define the detail). If the normal .FFT command is used, these varying time points need to be interpolated to a regular set to allow the FFT plot to be created.