Dual-band sigma-delta modulator for wideband receiver applications

Abstract

This work presents a new sigma-delta modulator (SDM) architecture for a wide bandwidth receiver. This architecture contains dualbandwidth for W-CDMA and GSM system applications. Low-distortion swing-suppressing SDM and interpolative SDM cascaded units are used together. Using the low-distortion swing-suppressing technique, the resolution can be improved even under non-linearity effects. The interpolative SDM extends the signal bandwidth and represses the high-band noise. The SDM used in the W-CDMA and GSM applications was designed and simulated using 0.25-mum 1P5M CMOS technology. The simulated peak SNDR of W-CDMA and GSM are 72/70 dB and 82/84 dB in Low-IF/Zero-IF standards.