Method for calibrating a pipelined continuous-time sigma delta modulator

摘要

Traditionally, pipelined continuous-time (CT) sigma-delta modulators (SDM) have been difficult to build due at least in part to the difficulties in calibrating the pipeline. Here, however, a pipelined CT SDM is provided that has an architecture that is conducing to being calibrated. Namely, the system includes a digital filter and other features that can be adjusted to account for input imbalance errors and well as quantization leakage noise.

主权项

1. A method for calibrating at least a portion of a pipelined continuous-time (CT) sigma-delta modulator (SDM), wherein the CT SDM includes a first stage, a second stage, a first digital-to-analog converter (DAC) coupled between the first and second stages, and a digital filter that is coupled to the first and second stages, wherein the second stage includes a second DAC, the method comprising:
determining a ratio of a gain of the first DAC to a gain of the second DAC; and adjusting a gain of a digital filter to be approximately equal to the ratio of the gain of the first DAC to the gain of the second.