Delta-sigma modulators are currently a very popular technique for making high-resolution
analog-to-digital and digital-to-analog converters. These oversampled data
converters have several advantages over conventional Nyquist-rate converters, including
an insensitivity to many analog component imperfections, a simpler antialiasing filter and
reduced accuracy requirements in the sample and hold. Though the initial uses of delta-sigma
modulators were in the audio field, the development of bandpass modulators opened
up the application range to radar systems, digital communication systems and instruments
which convert IF, or even RF, analog signals directly to digital form.
This thesis presents a method used to analyze and synthesize continuous-time
delta-sigma modulators for given specifications. A fourth-order prototype continuous-time
bandpass delta-sigma modulator employing g[subscript m]-LC resonator structure is demonstrated on
a PCB board and measurement results corroborate the theory. To allow the construction of
very high performance delta-sigma modulators, this thesis presents an architecture for a
multibit DAC constructed from unit elements which shapes element mismatches. Theoretical
analysis and simulation shows that this architecture greatly increases the noise attenuation
in the band-of-interest and facilitates the use of multibit quantization in delta-sigma
modulators. The methods presented in this thesis will allow high-frequency wideband
bandpass delta-sigma modulators to be constructed. / Graduation date: 1996
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34675 |
| Date | 03 April 1996 |
| Creators | Zhang, Bo |
| Contributors | Schreier, Richard |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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