Title :
Study of Q factor and loop delay effects of a continuous-time Δ Σ AD modulator
Author :
Lin, Haijun ; Motozawa, Atushi ; Ré, Pascal Lo ; Iizuka, Kunihiko ; Kobayashi, Haruo ; San, Hao
Author_Institution :
Gunma Univ. of Japan, Kiryu, Japan
Abstract :
This paper describes the design and analysis of a continuous-time bandpass ΔΣ AD modulator for RF sampling. We determined the SNDR degradation due to finite Q value of the loop resonator, and due to excess loop delay (ELD). SNDR was improved by 20 dB by adding a digital filter which compensates for the effect of finite Q value, and SNDR was further improved by 20 dB by feedforward with parameters optimized to compensate for ELD. We have confirmed the effectiveness of the digital filter and feedforward proposals using Matlab and SPICE simulations.
Keywords :
Q-factor; SPICE; analogue-digital conversion; delta-sigma modulation; digital filters; mathematics computing; resonators; AD modulator; Matlab; Q factor; SPICE simulations; bandpass modulator; continuous-time delta-sigma modulator; digital filter; loop delay; loop resonator; Band pass filters; Degradation; Delay effects; Digital filters; Digital modulation; Q factor; RF signals; Radio frequency; Sampling methods; Transfer functions; Continuous-time Δ Σ AD Modulator; ELD; Q value; RF sampling; Sub-sampling;
Conference_Titel :
ASIC, 2009. ASICON '09. IEEE 8th International Conference on
Conference_Location :
Changsha, Hunan
Print_ISBN :
978-1-4244-3868-6
Electronic_ISBN :
978-1-4244-3870-9
DOI :
10.1109/ASICON.2009.5351486
