A new optimization technique for coefficient scaling in sigma-delta modulators

Abstract

This article proposes a new method for scaling the output swing of the integrators in a sigma-delta modulator. The algorithm takes in consideration the relative effect on the output signal-to-noise ratio of the thermal noise from each integrator to find a set of coefficients which implements the desired transfer functions while reducing the signal swing at each node. Simulation results show that the last two integrators output swing can be reduced by 50% and 90% respectively for a 0.5 dB signal-to-noise ratio reduction.