Detection and Removal of Limit Cycles in Sigma Delta Modulators

Sigma delta modulation is a popular method for converting signals from analog to digital and vice-versa. However, sigma delta modulators (SDMs) may suffer from limit cycles, where the output bits may enter a repeating pattern. Current methods of preventing this phenomenon introduce unwanted noise, d...

Full description

Saved in:
Bibliographic Details
Published in:IEEE transactions on circuits and systems. I, Regular papers Regular papers, 2008-11, Vol.55 (10), p.3119-3130
Main Authors: Reiss, J.D., Sandler, M.
Format: Article
Language:English
Subjects:
Analog to digital converters
Analog-to-digital conversion (ADC)
Circuits
Conversion
Delta modulation
Delta-sigma modulation
Deltas
digital- to-analog conversion (DAC)
Disturbances
Dynamic range
Feedback
Frequency
Limit-cycles
Modulators
Noise shaping
Quantization
sigma delta modulation
Signal to noise ratio
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Sigma delta modulation is a popular method for converting signals from analog to digital and vice-versa. However, sigma delta modulators (SDMs) may suffer from limit cycles, where the output bits may enter a repeating pattern. Current methods of preventing this phenomenon introduce unwanted noise, do not always succeed, and are often implemented when not needed. We present a more effective method for detecting and removing unwanted limit cycles. This method includes adding a small disturbance to the input, which destroys the periodicity of sigma-delta analog-to-digital conversion (ADC) modulator's output sequence and thereby removes the limit cycles. Compared with conventional methods this method is simpler to implement, and the SDM has less signal-to-noise ratio (SNR) penalty and a higher allowed input dynamic range. Various implementations of the limit cycle detection and removal schemes are described for feedforward SDMs. Results are reported which demonstrate the success of these methods.
ISSN:1549-8328
1558-0806
DOI:10.1109/TCSI.2008.925078