Sigma delta modulation is a popular form of audio analogue-to-digital and digital-to-analogue conversion, but suffers from stability problems for many designs and many input signals. A general theory of stability in sigma delta modulators has been developed which predicts the stability of a high order one bit sigma delta modulator (SDM) under a variety of designs. In this paper, the theoretical approach to stability as it applies to boundedness of states is explained. Several low pass SDM designs are developed which are intended for audio analogue to digital conversion, and predicted results for stability of these designs are given. Stability is examined both in terms of the maximum allowable DC input amplitude and the theoretical sufficient conditions for stable behavior. Theoretical results are compared with simulated results, and where possible, with experimental results from a realisation of a third order SDM with adjustable parameters. Practical observations are then made concerning the effect of noiseshaping, pole/zero placement, and cut-off frequency on the stability.
Authors:
Mladenov, Valeri; Reiss, Joshua D.; Tsenov, Georgi
Affiliations:
Technical University of Sofia;Queen Mary, University of London(See document for exact affiliation information.)
AES Convention:
124 (May 2008)
Paper Number:
7440
Publication Date:
May 1, 2008
Subject:
Software, Instrumentation, and Measurement
Click to purchase paper as a non-member or you can login as an AES member to see more options.
No AES members have commented on this paper yet.
To be notified of new comments on this paper you can subscribe to this RSS feed. Forum users should login to see additional options.
If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.