Second-order continuous-time SD analog-digital converter (ADC) adopting self noise coupling

Abstract

The invention discloses a second-order continuous-time SD analog-digital converter (ADC) adopting self noise coupling. After input continuous signals pass through a second-order filter loop, a least significant bit part and a most significant bit part are output, wherein the most significant bit part is input into the second-order filter loop; after being input into a self noise coupling loop, the least significant bit part is divided into two paths; after passing through a delay unit, one path is input into a digital subtraction circuit; the other path is directly input into the digital subtraction circuit; the two paths of signals pass through the digital subtraction circuit, and return to a second-stage integrator in the second-order filter loop through a first analog-digital converter; and, after passing through a digital filter in a digital noise shaping loop, the processed least significant bit part is subjected to digital addition with the most significant bit part through a digital adder in the digital noise shaping loop, so that discrete digital output signals are obtained. By means of the SD ADC, noise leakage due to mismatching of an analog filter and the digital filter is reduced; the noise shaping effect is improved; and thus, the signal-to-noise ratio of a system is obviously improved.

Description

technical field [0001] The invention relates to the technical field of mixed-signal integrated circuit design, in particular to a second-order continuous-time SD analog-to-digital converter using self-noise coupling. Background technique [0002] With the rapid development of technologies such as voice control and voice recognition, people have higher and higher performance requirements for audio signal processing tools. Over the past few decades, the integrated circuit (IC) industry has evolved precisely according to the famous Moore's Law, which states that every 18 months, the integration of components will double, and the performance will double at the same time. [0003] In an integrated circuit, an analog-to-digital converter (ADC) is an essential module. For example, in an audio signal processing system, an SD analog-to-digital converter (Sigma-Delta ADC, ΣΔADC) converts the collected audio signal into a digital signal , so as to further transmit and process the sign...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a second-order continuous-time SD analog-to-digital converter that uses self-noise coupling, which can improve the conversion accuracy of SDADC, solve the impact of quantization noise caused by the quantization error of the quantizer on the signal SNDR and reduce the loop The noise leakage caused by the mismatch between the filter and the digital filter, so that the noise performance and other performance of the audio system can be improved

Images