DocumentCode :
2163701
Title :
Limit cycles in embedded high-order, lowpass sigma-delta modulators with distinct NTF zeros
Author :
Wong, Ngai ; Ng, Tung-Sang
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ., China
Volume :
2
fYear :
2002
fDate :
2002
Firstpage :
1043
Abstract :
In a related work by the authors, high-order sigma-delta (ΣΔ) modulators with distinct noise transfer function (NTF) zeros are decomposed into second-order and first-order subsystems, whose state-trajectories are then investigated by continuous-time embedding. This paper, based on the properties of these subsystems, furthers the study by introducing a scalable numerical method to locate the fixed-points on the generalized Poincare sections. A closed-form tangent linear manifold matrix for an arbitrary order modulator is derived, enabling the stability determination of the fixed-points and the accompanying limit cycles. Numerical examples show that the estimated DC input bound based on the boundary transition flow assumption cannot be relied on for modulators of order greater than four.
Keywords :
Poincare mapping; circuit stability; limit cycles; modulators; poles and zeros; sigma-delta modulation; transfer functions; DC input bound; boundary transition flow assumption; closed-form tangent linear manifold matrix; continuous-time embedding; distinct noise transfer function zeros; first-order subsystem; fixed-points; generalized Poincare sections; high-order sigma-delta modulators; limit cycles; low-pass sigma-delta modulators; scalable numerical method; second-order subsystem; stability; state-trajectories; Delta-sigma modulation; Digital signal processing; Limit-cycles; Matrix decomposition; Nonlinear equations; Stability; State feedback; Transfer functions;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Digital Signal Processing, 2002. DSP 2002. 2002 14th International Conference on
Print_ISBN :
0-7803-7503-3
Type :
conf
DOI :
10.1109/ICDSP.2002.1028269
Filename :
1028269
Link To Document :
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