Continuous-Time Delta-Sigma Modulators for High-Speed A/D Conversion

Theory, Practice and Fundamental Performance Limits
2000
ISBN: 978-1-4757-8346-9
Verlag: Springer US

Buch, Englisch, Band 521, 250 Seiten, Format (B × H): 152 mm x 229 mm, Gewicht: 410 g

Reihe: The Springer International Series in Engineering and Computer Science

Among analog-to-digital converters, the delta-sigma modulator has cornered the market on high to very high resolution converters at moderate speeds, with typical applications such as digital audio and instrumentation. Interest has recently increased in delta-sigma circuits built with a continuous-time loop filter rather than the more common switched-capacitor approach. Continuous-time delta-sigma modulators offer less noisy virtual ground nodes at the input, inherent protection against signal aliasing, and the potential to use a physical rather than an electrical integrator in the first stage for novel applications like accelerometers and magnetic flux sensors. More significantly, they relax settling time restrictions so that modulator clock rates can be raised. This opens the possibility of wideband (1 MHz or more) converters, possibly for use in radio applications at an intermediate frequency so that one or more stages of mixing might be done in the digital domain.
covers all aspects of continuous-time delta-sigma modulator design, with particular emphasis on design for high clock speeds. The authors explain the ideal design of such modulators in terms of the well-understood discrete-time modulator design problem and provide design examples in Matlab. They also cover commonly-encountered non-idealities in continuous-time modulators and how they degrade performance, plus a wealth of material on the main problems (feedback path delays, clock jitter, and quantizer metastability) in very high-speed designs and how to avoid them. They also give a concrete design procedure for a real high-speed circuit which illustrates the tradeoffs in the selection of key parameters. Detailed circuit diagrams, simulation results and test results for an integrated continuous-time 4 GHz band-pass modulator for A/D conversion of 1 GHz analog signals are also presented.
concludes with some promising modulator architectures and a list of the challenges that remain in this exciting field.

Zielgruppe

Research

Autoren/Hrsg.

Snelgrove, W. Martin

Cherry, James A.

Fachgebiete

• Technische Wissenschaften Energietechnik | Elektrotechnik Elektrotechnik
• Technische Wissenschaften Elektronik | Nachrichtentechnik Elektronik Bauelemente, Schaltkreise

Inhaltsverzeichnis

Delta-Sigma Modulation Concepts.- Designing Continuous-Time Modulators.- Delta—Sigma Modulator Implementation Issues.- Excess Loop Delay.- Clock Jitter and Quantizer Metastability.- A High-Speed Band Pass ??M Design Procedure.- A 4GHZ Fourth-Order Band Pass ? ?M.- Conclusions.