Importance

Loading Importance Indicators...

Abstract

Delta sigma modulators for accepting input signals having amplitudes up to -1 dB of full-scale and a center frequency (F.sub.S) in the range ?F.sub.S /90, 44F 90!, and which are not prone to internal overflow, require few circuit parameters, and yield a signal transfer function with the inherent property that the modulator magnitude response is close to unity gain in the frequency region of interest include, in one embodiment, a pair of cascaded integrators, a unit delay element coupled to the output of the second integrator, an analog-to-digital (A/D) converter, and a one-bit digital-to-analog (D/A) converter controlled by output signals from the A/D converter. A first differential summing junction coupled to the output of the D/A converter is responsive to delta sigma modulator input signals. A second differential summing junction, coupled to the output of the first differential summing junction, is also coupled to receive a feedback signal from the second integrator. A third differential summing junction, coupled to the output of the unit delay element, also receives feed-forward signals from the second integrator.

Loading the Abstract Image...

First Claim