Dual-mode Continuous-Time Quadrature Bandpass ΔΣ modulator with Pseudo-random Quadrature mismatch shaping algorithm for Low-IF receiver application

This work presents a 2 nd -order, multi-bit Continuous-time Quadrature Bandpass Delta-Sigma (CT QBP ΔΣ) modulator with a Pseudo-random Quadrature Mismatch Shaping (PQMS) algorithm for GSM-EDGE/Bluetooth Low-IF receiver. CT QBP ΔΣ modulator is vulnerable to mismatches between its in-phase and quadrat...

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Bibliographic Details
Main Authors: Chen-Yen Ho, Yung-Yu Lin, Tsung-Hsien Lin
Format: Conference Proceeding
Language:English
Subjects:
Bluetooth
Capacitors
Circuits
Computed tomography
Delta modulation
Dynamic range
Filters
Noise shaping
Radio frequency
Signal to noise ratio
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Summary:This work presents a 2 nd -order, multi-bit Continuous-time Quadrature Bandpass Delta-Sigma (CT QBP ΔΣ) modulator with a Pseudo-random Quadrature Mismatch Shaping (PQMS) algorithm for GSM-EDGE/Bluetooth Low-IF receiver. CT QBP ΔΣ modulator is vulnerable to mismatches between its in-phase and quadrature (I/Q) paths that can dramatically degrade its Signal to Noise-plus-Distortion Ratio (SNDR) and image-rejection ratio (IRR). This modulator incorporates a proposed PQMS to mitigate the main I/Q mismatch source from multi-bit I/Q DAC units to improve IRR The CT QBP ΔΣ modulator is fabricated in a 0.18-μm CMOS process. With the proposed PQMS, the modulator achieves a dynamic range of 82/69 dB in 200 kHz/1 MHz, respectively. The IRR is better than 65 dB with -4 dBFS input level and the whole CT QBP ΔΣ modulator consumes less than 8.5 mW in both modes from a 1.8-V supply voltage.
ISSN:0271-4302
2158-1525
DOI:10.1109/ISCAS.2010.5537126