Abstract
In this article, a detailed theoretical analysis of the impact of finite gain-bandwidth product (GBW) in amplifiers, excess loop delay, and a hysteretic quantiser on a second order, 3-bit, continuous-time sigma-delta (CT ) modulator with decaying exponential feedback pulses has been accomplished. A “short” exponential pulse – namely, an exponential pulse whose time constant is lower than the pulse width – was used in order to improve jitter rejection. An overall noise transfer function (NTF) that includes the effect of the three non-ideal effects was analytically calculated using the modified Z-transform method. The evolution of the NTF poles and zeroes locus in the z-plane is obtained when these effects are taken into account separately or combined. System-level simulations have been also carried out in order to validate the proposed theoretical study. The stability of a modulator with “short” exponential feedback pulses is higher than that of a modulator with rectangular ones when finite GBW or excess loop delay are included. Finally “short” exponential pulses and “narrow” rectangular ones are proved to be equivalent from the stability viewpoint.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.