Research And Design Of High Precision Sigma-Delta Modulator In Seismic Electrical Acquisition Station

With the continuous exploration of deep geophysical exploration,relying solely on a single geophysical exploration method has been unable to meet the needs of China's exploration work,so joint seismic and electrical exploration technology was proposed.The key to the realization of the technology lies in the design of an integrated front-end hybrid acquisition station for seismic and electrical data acquisition instruments.After research,we found that the main difference between the seismic acquisition instrument and the electrical acquisition instrument is the front-end adopting analog circuits.After taking into account this difference,it is proposed to design a high-precision Sigma-Delta analog-to-digital conversion chip for seismic exploration and joint exploration to provide a solution for the development of highprecision seismic electric distributed hybrid exploration and acquisition systems.For an excellent Sigma-Delta A/D converter chip,the modulator design plays an invaluable role in improving the performance and reliability of the entire chip.The core technology of the Sigma-Delta modulator is oversampling and noise shaping.Sigma-Delta technology is compatible with the CMOS standard digital process,it can be integrated with a digital circuit as an integrated chip,which achieves high linearity,with the continuous development of related technologies,its accuracy can reach 16-24 bits.This design combines the design flow of a complete single-ring,fourth-order,onebit,high-precision sigma-delta modulator to implement the overall architecture of the modulator.This design specifically studies the research background and status of the ADC at home and abroad,the Sigma-Delta modulator Principles and classifications,system-level design and simulation of Sigma-Delta Modulators,sigma-delta modulator circuit schematics and layout design,finally analyzing the design experience.In the circuit design process,we adopts a feedforward sum circuit in order to reduce the output of each stage integrator.A fourth-order modulator is designed to improve the signal-tonoise ratio.A one-stage quantizer is used to reduce the nonlinearity,and the consumption parameters of the system were optimized in order to reduce the power.The integrators,amplifiers,comparators,summation circuits,clock circuits,etc.in the Sigma-Delta modulator were studied in detail theoretically.Then every module was implemented using Toolbox and Simulink in MATLAB to realize system-level design and behavioral level simulation.We did the circuit design and simulation of each module under Cadence environment.Finally,We realized the design of a high-precision,high-noise ratio fourth-order single-loop one-bit-quantization CIFF Sigma-Delta modulator.