Accurate Fourier analysis for circuit simulators

A new approach to Fourier analysis within the context of circuit simulation is presented that is considerably more accurate and flexible than the traditional SPICE approach. It is based on the direct computation of the Fourier integral rather than on the discrete Fourier transform and so it is not subject to aliasing. It can be used to accurately compute a small number of Fourier coefficients for broad-spectrum signals such as those generated by mixers, /spl Sigma//spl Delta/ and pulse-width modulators, DACs, and SC-filters. In addition, techniques that reduce errors and provide the ability to resolve harmonics 120 dB-140 d below the carrier are presented.<
>