A Power-Efficient Tunable Narrow-Band Digital Front End for Bandpass Sigma-Delta ADCs in Digital FM Receivers

作者：Shahein Ahmed^*; Afifi Mohamed; Becker Markus; Lotze Niklas; Manoli Yiannos

来源：IEEE Transactions on Circuits and Systems II-Express Briefs, 2010, 57(11): 883-887.

DOI：10.1109/TCSII.2010.2082891

• Cascaded integrator comb (CIC)
• digital front end (DFE)
• frequency modulation (FM)
• low power
• polyphase decimator
• tunable

A power-efficient narrow-band tunable digital front end (DFE) for bandpass sigma-delta (Sigma Delta) analog-to-digital converters is presented. The proposed architecture introduces a new system topology, splitting the down converter into two mixers and placing a cascaded integrator-comb decimation stage between the two mixers. The first mixer is a quadrature mixer that works at a quarter of the sampling frequency. It is followed by a complex mixer with a tunable frequency. The Sigma Delta modulator and the DFE are digitally controlled. The proposed architecture is first analyzed on the system level and then synthesized in a 130-nm CMOS technology. A reduction in the power consumption of about 50% has been achieved by the proposed architecture when compared with the conventional approach.