The Design And Signal Integrity Analysis Of The AD Conversion Module Applied To The Wireless Acquisition Node Of Seismic Exploration

Seismic exploration has become the mainstream method in the oil and gas resources exploration industry.Compared with foreign countries,traditional wired seismic exploration acquisition systems are still commonly used in China,which are easily restricted by the natural environment in practical applications,making it difficult to complete large-scale and high-rate seismic exploration in complex terrain.In this context,the group designed a wireless acquisition node for seismic exploration,in which the AD conversion module is the core module and its performance directly determines whether the seismic data acquired are valid.Therefore,it is important to design a high-precision and high-sampling-rate AD conversion module for application.The difficulty in the design of AD conversion modules is that Integrated Circuit devices with high switching speed in the circuit will inevitably cause signal integrity problems,resulting in the AD conversion module not working properly.The success rate of the traditional design method is related to the personal experience of the engineer,and it is not applicable when designing high-speed,high-frequency and high-precision AD conversion modules.To address this problem,this thesis completes the design of the AD conversion module using signal integrity analysis,which provides a basis for optimizing the circuit by establishing a mathematical-physical model of the devices in the circuit to quantify and analyze the interference,and the AD conversion module designed on this basis has a high degree of reliability and reproducibility.In this thesis,according to the seismic exploration theory and signal integrity analysis,and relying on the overall framework of the seismic exploration wireless acquisition node developed by the research group,two types of AD conversion modules,single-component and three-component,are designed.The main research contents are as follows:(1)With reference to the performance parameters of mainstream seismic survey wireless acquisition nodes,the requirements of sampling rate,conversion accuracy,storage capacity and noise immunity are proposed for the AD conversion module.On this basis,the chip selection is completed and the hardware circuits of control,storage and power supply are designed.(2)A comprehensive signal integrity analysis of the AD conversion module was carried out:different termination schemes and circuit routing layout were selected to improve the reflection and crosstalk problems of high-frequency transmission lines and verify their loss characteristics;the DC voltage drop characteristics and decoupling characteristics of the AD conversion module were optimized to improve the power supply integrity problems on the power supply network;the analog signal input circuit was designed with differential coupling and its effectiveness was verified.(3)By programming the hardware interface,selecting the corresponding communication protocols for different communication objects,real-time data transmission is achieved and congestion is avoided.In order to ensure that the data is still intact when real-time transmission is not possible,the management of the TF card is completed with the help of porting the FatFS file system,thus enabling local storage of data.After completing the development work,the AD conversion module was tested under the ideal indoor state and the normal outdoor working state.In the indoor test,accurate acquisition conversion and storage of preset signals were achieved;in the outdoor test,joint debugging with other modules was conducted The AD conversion module could accurately execute the acquisition and transmission instructions of the control center.The tests showed that the AD conversion module developed through signal integrity analysis met the design requirements.