Accurate and Efficient PSD Computation in Mixed-Signal Circuits: A Time-Domain Approach

The aim of this brief is twofold. On one side, the time-domain technique presented by Vasudevan to obtain the average and instantaneous power-spectral density of electrical variables in analog circuits characterized by (non)stationary noise sources is rigorously extended to the wide class of analog mixed-signal circuits modeled as hybrid dynamical systems. On the other side, an efficient numerical implementation is proposed to overcome the computational effort required by the original approach. The reliability of the method is first tested through the analog ring oscillator analyzed by Vasudevan. A fractional delta-sigma phase-locked loop with dithering is then simulated and the obtained results are partially validated through experimental measurements.