Reconfiguration of Cascade ΣΔ Modulators for Multistandard GSM/Bluetooth/UIMTS/WLAN Transceivers

This paper presents design considerations for cascade Sigma-Delta Modulators (ΣΔMs) included in multi-standard wireless transceivers. Four different standards are covered: GSM, Bluetooth, UMTS and WLAN. A top-down design methodology is proposed to find out the optimum modulator architecture in terms of circuit complexity and reconfiguration parameters. The selected 2-1^(L-2) expandible YAM is high-level sized and several reconfiguration strategies are adopted at both architecture- and circuit-level in order to adapt the modulator performance to the different standards requirements with adaptive power consumption. Time-domain simulations are shown to validate the presented approach.