Title :
Linearity enhancement in a configurable sigma-delta modulator
Author :
Rusu, Ana ; Jose, Babita Roslind ; Ismail, Mohammed ; Tenhunen, Hannu
Author_Institution :
IMIT/LECS, R. Inst. of Technol., Stockholm, Sweden
Abstract :
A highly linear sigma-delta modulator for dual-standard receivers is presented. The modulator makes use of low-distortion sigma-delta modulator architecture to attain high linearity over a wide bandwidth. The dual-band modulator employs a 2nd order single-bit sigma-delta modulator with feedforward path for GSM mode and a 4th order modified cascaded modulator with single-bit in the first stage and 4-bit in the second for WCDMA mode. The modulator is designed in TSMC 0.18μm CMOS technology and operates at 1.8 supply voltage. It achieves in GSM/WCDMA mode a peak SNDR of 83/75dB, a 96/84dB SFDR and an IMD3 of -93/-82dB for an OSR of 160/16.
Keywords :
CMOS integrated circuits; cellular radio; code division multiple access; radio receivers; sigma-delta modulation; 0.18 micron; 1.8 V; 4 bit; CMOS technology; GSM mode; WCDMA mode; configurable sigma-delta modulator; dual-band modulator; dual-standard receiver; feedforward path; fourth order modified cascaded modulator; linear sigma-delta modulator; linearity enhancement; low-distortion sigma-delta modulator architecture; second order single-bit sigma-delta modulator; Bandwidth; CMOS technology; Circuits; Delta-sigma modulation; Dynamic range; GSM; Linearity; Multiaccess communication; Telecommunication standards; Wideband;
Conference_Titel :
IEEE-NEWCAS Conference, 2005. The 3rd International
Print_ISBN :
0-7803-8934-4
DOI :
10.1109/NEWCAS.2005.1496663
