A delay-based complex double-sampled resonator for use in ƒ_s/4 quadrature bandpass ΣΔ modulators

Abstract

This paper extends the circuit implementation of a complex ƒ_s/4 resonator based on integrators towards double-sampling. Next, an improved double-sampled circuit implementation of a complex ƒ_s/4 resonator based on delays is introduced. The key features of the proposed circuit are that mismatch does not affect the center frequency nor limit the Q-factor of the resonator and lower sensitivity towards opamp gain. To verify the analytical results extracted in this paper, simulation results are presented.