Center frequency and bandwidth tunable band pass delta sigma modulator

Abstract

In conventional tunable band pass delta sigma modulators one parameter is used to only tune the center of desired frequency band. This paper presents a new method for tuning both the center frequency and bandwidth by using separate independent tuning parameters for each pair of NTF complex conjugate zeros. Spreading NTF zeros in signal band results in higher SQNR. A 4th order low distortion band pass delta sigma modulator with center frequency and bandwidth tunability based on proposed method is simulated to verify theory. System level simulations show a wide range of center frequency and bandwidth tunability without performance degradation.