High-precision and low-distortion digital-analog converter

Abstract

The invention relates to a high-precision and low-distortion digital-analog converter which comprises an analog adder / subtractor, first and second analog integrators, an analog adder, an analog-digital converter, first, second and fourth gain amplification stages, an analog gain stage and a feedback gain amplification stage. A signal output end OUTPUT is connected with an output end of the analog-digital converter, a second-order DEM (dynamic element matching) module is arranged between the analog-digital converter and the analog adder / subtractor, an input end of the second-order DEM module is connected with the output end of the analog-digital converter, and an output end of the second-order DEM module is connected with an input end of the analog adder / subtractor by a digital-analog converter. The high-precision and low-distortion digital-analog converter has the advantages that owing to a feedback factor adding mode, zero points are imported into noise transfer functions, accordingly, noise power in signal base bands can be reduced, the signal-to-noise ratio of the high-precision and low-distortion digital-analog converter can be increased, and the system precision of the high-precision and low-distortion digital-analog converter can be improved; second-order suppression can be carried out on mismatched noise by the aid of second-order sigma-delta DEM technologies, accordingly, the signal-to-noise distortion ratio of the integral sigma-delta analog-digital converter can be increased, and the spurious-free dynamic range of the integral sigma-delta analog-digital converter can be expanded.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a high-precision and low-distortion digital-to-analog converter. Background technique [0002] In existing Σ-Δ ADCs, whether it is a single-loop high-order structure or a multi-level cascaded (MASH) structure, it mainly improves its signal-to-noise ratio by reducing the power of quantization noise, and then improves its accuracy. There are two main technologies, one is high-order suppression of quantization noise to improve its conversion accuracy, that is, through the design of the Σ-Δ system structure, especially the setting of the number of integrator stages and inter-stage gain, the quantization noise is passed through a high First-order noise shaping, thereby improving its in-band signal-to-noise ratio and converter accuracy; the inter-stage gain usually adopts the gain value under the traditional structure. However, the converter accuracy achieved by the traditional struct...

AI Technical Summary

Problems solved by technology

Multi-digit digital-to-analog converters include current steering structure and switched capacitor array structure, however, due to temperature drift and process deviation, there is a matching error between a large number of current source units or capacitor units in the converter, which appears in the output spectrum as Poor linearity, which severely affects the signal-to-noise-distortion ratio (SNDR) and spurious-free dynamic range (SFDR) of the entire sigma-delta ADC

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