Digital-analog converter with high signal noise distortion ratio

Abstract

The invention relates to a digital-analog converter with a high signal noise distortion ratio. The digital-analog converter comprises a two-order dynamic component matching and modulating module, a switched capacitor array, an adder and a low-pass filter; the two-order dynamic component matching and modulating module is used for matching and modulating digital signals into 128-bit digital signals; the switched capacitor array is used for converting the digital signals input by the two-order dynamic component matching and modulating module, into voltage signals; the adder is used for adding the voltage signals input by the switched capacitor array; the low-pass filter is used for filtering a total voltage signal input by the adder. The switched capacitor array is composed of 64 switched capacitor units. According to the technical scheme, by means of selecting device array units through digital signals subjected to high-order modulation, device selection and positioning is achieved through pointer signals, mismatch signals are reshaped and suppressed, the mismatch noise in the analog output signals of the digital-analog converter is filtered through the low-pass filter, the noise is substantially removed from signal baseband, and key dynamic performance parameters of the digital-analog converter are increased.

Description

technical field [0001] The invention relates to a digital-to-analog converter with high signal-to-noise-to-distortion ratio. Background technique [0002] In traditional capacitive digital-to-analog converters, the unit array is composed of a large number of switches and capacitor units. Due to the deviation of the manufacturing process, there is a mismatch error of up to 20% between these capacitor units, which seriously affects the linearity of the digital-to-analog converter. Accuracy and spurious-free dynamic range performance; commonly used traditional mismatch noise digital correction methods include single-stage averaging technology, randomization technology, etc. The single-stage averaging technique calibrates the multi-digit digital-to-analog converter by ensuring that each unit has the same probability of being used. The specific process is that for each input digital value, a register is used to store the capacitor unit being used, and a barrel-type A shifter is ...

AI Technical Summary

Problems solved by technology

It can be seen that the traditional mismatch noise digital correction method suppresses the mismatch noise to some extent, improves the spurious-free dynamic range of the output signal and the linearity performance of the circuit, but does not eliminate the mismatch noise fundamentally, so The overall signal-to-noise-distortion ratio does not degrade, and the mismatch noise remains in the signal band

For the overall system, the signal quality has not improved fundamentally

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