ContinuousTime DeltaSigma Modulators for HighSpeed A/D Conversion
Theory, Practice and Fundamental Performance Limits
Creator  
Publisher 
2000

ISBN  0792386256, 9780792386254,

Language 
English

Category  
Subject  Analogtodigital converters. Analogtodigital converters.  fast  (OCoLC)fst00808296 Continuoustime filters. Continuoustime filters.  fast  (OCoLC)fst00876780 Modulators (Electronics) Modulators (Electronics)  fast  (OCoLC)fst01024519 TECHNOLOGY & ENGINEERING  Electronics  Circuits  General.  bisacsh TECHNOLOGY & ENGINEERING  Electronics  Circuits  Integrated.  bisacsh 
Description
Among analogtodigital converters, the deltasigma 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 deltasigma circuits built with a continuoustime loop filter rather than the more common switchedcapacitor approach. Continuoustime deltasigma 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. ContinuousTime DeltaSigma Modulators for HighSpeed A/D Conversion: Theory, Practice and Fundamental Performance Limits covers all aspects of continuoustime deltasigma modulator design, with particular emphasis on design for high clock speeds. The authors explain the ideal design of such modulators in terms of the wellunderstood discretetime modulator design problem and provide design examples in Matlab. They also cover commonlyencountered nonidealities in continuoustime 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 highspeed designs and how to avoid them. They also give a concrete design procedure for a real highspeed circuit which illustrates the tradeoffs in the selection of key parameters. Detailed circuit diagrams, simulation results and test results for an integrated continuoustime 4 GHz bandpass modulator for A/D conversion of 1 GHz analog signals are also presented. ContinuousTime DeltaSigma Modulators for HighSpeed A/D Conversion: Theory, Practice and Fundamental Performance Limits concludes with some promising modulator architectures and a list of the challenges that remain in this exciting field.