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Adaptive noise cancellation for second-order delta-sigma A/D convertersBribech, Habib 18 September 1992 (has links)
Oversampled analog-to-digital (A/D) converter architectures have been receiving
increased attention for high-precision A/D converters. These architectures offer the
means of exchanging resolution in time for that in amplitude. Among these
oversampled A/D converters, delta-sigma modulators are the most popular method
used due to their simplicity in the analog circuitry. The analog integrators in delta-sigma
modulators suffer from non-idealities such as capacitor mismatches and finite
op-amp gain. In the dual quantizer A/D converters, the system relies on the perfect
matching of the analog and digital transfer functions to cancel the quantization noise.
However, the non-ideality of the analog parameters makes this matching hard to
achieve.
In this thesis, an off-line adaptive scheme is presented to estimate the non-ideal
parameters of the analog section for the second-order delta-sigma modulator. These
estimates are then used in the digital part to reduce the quantization noise. The least-mean-
square (LMS) algorithm is used to adaptively estimate the analog parameters. / Graduation date: 1993
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