Four order single loop local negative feedback Sigma-Delta modulator

Abstract

The invention discloses a four order single loop local negative feedback Sigma-Delta modulator, belonging to the technical field of CMOS analog-to-digital converter (ADC) design. The modulator comprises a high-pass filter and a quantizer which are connected; the high-pass filter is used for filtering noise signals in input signals and determining signal transmission functions and noise transmission functions of the input signals; the quantizer is used for carrying out quantification treatment on the input signals filtered by the high-pass filter. By using the high-pass filter to determine thenoise transmission functions and signal transmission functions of the Sigma-Delta modulator, the invention better restrains noises in a tape and is suitable for ADC design with low oversampling frequency and high precision; in addition, using Verilog-A hardware language to establish behavioural modeling, the invention can precisely simulates circuit function, in particular in simulation of mixed-signal circuits, thus greatly shortening simulation time and improving simulation efficiency.

Description

technical field [0001] The invention relates to the technical field of CMOS analog-to-digital converter design, in particular to a fourth-order single-loop local negative feedback Sigma-Delta modulator. Background technique [0002] In recent years, with the increasing demand for high-precision analog-to-digital converters (ADC), and the difficulty of traditional Nyquist ADCs (Nyquist ADC) to achieve high-resolution (above 16bit) analog-to-digital conversion, Sigma-DeltaADC It has become a very attractive design technique in the field of analog-to-digital converters. The types of traditional Nyquist ADC are mainly divided into successive approximation type, integral type, flash type and pipeline type, etc. Due to the limitation of manufacturing process, these different types of Nyquist ADC make it impossible for Nyquist ADC to achieve high-resolution analog-to-digital conversion; In addition, in the Nyquist ADC, because the transition band of the anti-aliasing filter is ver...

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Problems solved by technology

[0006] In order to solve the existing Sigma-Delta modulator's problems such as large circuit overhead, high design difficulty, fast signal-to-noise ratio drop and poor stability, the present invention provides a fourth-order single-loop local negative feedback Sigma-Delta modulator, said The modulator includes a high-pass filter and a quantizer, the high-pass filter is connected to the quantizer; the high-pass filter is used to filter the noise signal in the input signal, and determine the signal transfer function and the noise transfer function of the input signal; The quantizer is used to quantize the input signal filtered by the high-pass filter

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