A modulator and its design method

Abstract

The invention discloses a modulator and a designing method thereof. The modulator comprises an analog filter, an analog adder, a multi-position quantizer, a digital loop filter, and a multi-position feedback digital-to-analog converter (DAC), wherein the analog filter is used for pre-modulating input analog signals, the analog adder is used for summing the analog signals, the multi-position quantizer is used for converting the sum of the analog signals into multi-position digital signals and outputting the multi-position digital signals, the digital loop filter is used for filtering the multi-position digital signals output by the multi-position quantizer, and the multi-position feedback digital-to-analog converter is used for converting the filtered multi-position digital signals into feedback analog signals. By the designing method disclosed by the invention, a stable modulator can be structured fast and conveniently; and as the digital loop filter is adopted to shape quantized noise and mismatched noise, the modulator not only has high stability, but also has good noise shaping capability, can effectively solve the non-linear problem of the multi-position feedback DAC, and can be used for high-speed and high-precision analog-to-digital conversion.

Description

technical field [0001] The present invention relates to analog-to-digital conversion, in particular to a modulator and its design method. Background technique [0002] Since the Delta-Sigma (Δ-∑) modulator needs to be oversampled when working, traditionally, the ADC (analog-to-digital converter) based on the Delta-Sigma modulator is mainly used in low-speed, high-precision fields, such as: audio systems, instruments and equipment Etc., with the development of communication systems towards broadband, the demand for high-speed, high-precision ADCs is increasing day by day. To achieve high-speed and high-precision performance, the Delta-Sigma modulator must reduce the oversampling rate, and at the same time, it is necessary to increase the order of the loop filter or increase the number of bits of the quantizer to compensate for the loss of the signal-to-noise ratio. [0003] Although increasing the order of the loop filter or increasing the number of bits of the quantizer are...

AI Technical Summary

Problems solved by technology

Low-order mismatch noise shaping DEM technology can weaken the influence of multi-bit feedback DAC nonlinearity to varying degrees, but they have high noise floor, large in-band harmonic spurs, and DAC noise and harmonic distortion fluctuate with the input signal amplitude. Problem; high-order mismatch noise shaping DEM technology can better weaken the influence of multi-bit feedback DAC nonlinearity, however, they not only have complex circuit structures, but also have instability problems

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