Advertisement

Integrated circuit design (I)

A 17-bit 40kSample/s fourth-order cascade Sigma-Delta modulator
  • Fernando Medeiro
  • Angel Pérez-Verdú
  • Angel Rodríguez-Vázquez
Chapter
Part of the The Springer International Series in Engineering and Computer Science book series (SECS, volume 480)

Abstract

Low-order (first- and second-) ΣΔ modulation-based A/D converters [Agra83] [Cand85] [Inos62] [Leun88] [Plass78] are very interesting for mixedsignal applications due to their small analog circuitry content, robustness and easy implementation. The second-order architecture [Agra83] [Bose88b] [Cand85] is preferred to the simpler first-order one because it is less sensitive to the correlation between the input and the quantization noise, which reduces the presence of pattern noise [Cand81], and has been largely used in various industrial applications. In any case, to reach a given resolution the oversampling ratio (M) must be kept constant, so that an increase in bandwidth implies a proportional increase in the clock frequency. For example, if a 16bit resolution, is required for a second-order architecture, M must equal at least 256, which for a 2-kHz bandwidth (typical in energy metering systems) pushes the clock frequency up to 1.024MHz. In audio band (20kHz), a 10.2MHz clock rate would be needed, while for video, up to 5MHz, 2.56GHz! Apart from the necessary increase in power consumption, increasing the clock frequency generates additional problems such as jitter, switching noise, etc.

Keywords

Clock Frequency Quantization Noise Input Level Integrator Weight Effective Resolution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer Science+Business Media Dordrecht 1999

Authors and Affiliations

  • Fernando Medeiro
    • 1
  • Angel Pérez-Verdú
    • 1
  • Angel Rodríguez-Vázquez
    • 1
  1. 1.Universidad de SevillaSpain

Personalised recommendations