Volume 41, Numbers 2-3, 209-222, DOI: 10.1023/B:ALOG.0000041637.75702.c3

A Non-Feedback Δ-Σ Modulator for Digital-to-Analog Conversion Using Digital Frequency Modulation

Dag T. Wisland, Mats E. Høvin and Tor S. Lande

From the issue entitled "ICECS'02"

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Abstract

This paper describes a novel noise-shaping Delta-Sgr modulator for D/A-conversion which has no global feedback. The proposed topology is well suited for a pipelined clocking scheme allowing increased oversampling ratios for both first and higher order modulators. The maximum clock-frequency of the new modulator is limited only by the delay through one single accumulator regardless of modulator order, which represents a huge saving compared to the conventional modulator. The converter is very modular and scales easily to higher modulator orders. Still the proposed topology is mathematically equivalent to the classical Delta-Sgr modulator. Theoretical analysis and circuit simulations for a first- and second-order modulator are presented. The first-order circuit has been implemented in a FPGA-circuit from Altera and measured results are presented.

sigma-delta - data converters - non-feedback

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