Open AccessImproved design of noise transfer functions with monotonic passband response for Delta‐Sigma modulators
Author(s) -
Kidambi Sunder
Publication year - 2020
Publication title -
iet circuits, devices and systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.251
H-Index - 49
ISSN - 1751-8598
DOI - 10.1049/iet-cds.2019.0347
Subject(s) - passband , monotonic function , delta sigma modulation , bilinear transform , stopband , control theory (sociology) , transfer function , elliptic filter , noise (video) , mathematics , filter (signal processing) , band pass filter , signal (programming language) , prototype filter , filter design , algorithm , computer science , electronic engineering , digital filter , engineering , mathematical analysis , bandwidth (computing) , telecommunications , control (management) , electrical engineering , artificial intelligence , image (mathematics) , computer vision , programming language
A method for the design of a noise transfer function (NTF) is presented in which the stopband of a continuous‐time high‐pass filter with monotonic passband characteristics is minimised by optimally placing an arbitrary number of imaginary‐axis zeros. Towards this end, the Papoulis, Halpern, and least‐squares monotonic polynomials have been used in the high‐pass filter design. The NTF is derived by applying the bilinear transformation on a continuous‐time high‐pass filter that minimises the in‐band energy and satisfies all the realisability constraints of a Delta‐Sigma modulator (DSM). By way of examples, it is shown that the signal‐to‐quantisation noise ratio achieved by the NTF designed by the proposed method is higher than that obtained by the NTF designed using a recently published method. The signal‐to‐noise ratio of the NTF designed with the proposed method is higher for a wide range of signal amplitude.