TABLE OF CONTENTS AHMED GHARBIYA, TREVOR C. CALDWELL, AND D. A. JOHNS
Department of Electrical and Computer Engineering, University of Toronto
10 King's College Rd., Toronto, Ontario, CANADA, M5S 3G4
This paper is mainly tutorial in nature and discusses architectures for oversampling converters with a particular emphasis on those which are well suited for high frequency input signal bandwidths. The first part of the paper looks at various architectures for discrete-time modulators and looks at their performance when attempting high speed operation. The second part of this paper presents some recent advancements in time-interleaved oversampling converters. The next section describes the design and challenges in continuous-time modulators. Finally, conclusions are made and a brief summary of the recent state of the art of high-speed converters is presented.
Keywords: oversampling, delta-sigma, analog-to-digital
Data conversion is an important operation that finds applications in many circuits today. Delta-sigma ( ??) modulation is a relative simple and low cost means of performing data conversion. While ?? modulators can obtain a high dynamic range and excellent linearity with the use of a 1-bit quantizer, they are most often found in low-frequency applications since they oversample the data to achieve a high signal-to-noise ratio (SNR), thus limiting the input bandwidth by the speed at which the sampler can operate.
The sampler in a ?? modulator must operate at a speed much greater than the bandwidth of the input signal since it must oversample the data. When standard CMOS technology is used, the...
