Research On The Software Of Signal And Protocol Analysis Based On Digital Oscilloscope

With the continuous improvement of communication data link,the high speed signal measurement tools and measurement accuracy are highly required by engineers.As the most important instrument in the field of communication and electronic measurement,the performance of the oscilloscope should be improved urgently,which will bring a great challenge to its manufacturers.In response to this challenge,oscilloscope vendors have to launch more oscilloscopes with better performance constantly.Since the fierce competition among oscilloscope suppliers,the gap of the performance of the current hardware products is gradually narrowing.In the meantime,many companies have been tend to develop off-line data analysis software which can process data stronger and faster,with more comprehensive measurement functions,easier to extend and maintain,and the analysis result should be more convenience to store,share and carry.This software relies on oscilloscope to acquire data,as well as computer to process and analyze data,it has no real-time requirements,and engineers can perform a broader operation with it.Therefore it will have extensive application prospects in communications,test and measurement industry,and has a very high practical applicability and research value certainly.Depending on the National Key Scientific Instrument and Equipment Development Project,this thesis will focus on developing an offline data analysis software,the main function of the software included:the fundamental waveform measurements,such as the basic waveform parameters(period,amplitude,peak-peak value,duty cycle,rising time,dropping time,etc.),the creation and measurement of eye diagram(eye height,eye width,extinction ratio,etc.),the creation of eye diagram template,and the analysis of SDH protocol.The main task and innovative points of this thesis can be listed as following:1.In this thesis,the measurement algorithms of the basic parameters such as period,frequency,amplitude,mean and root mean square(RMS),rise time,fall time measurement algorithms and mathematical model were developed.In addition,the design flow chart and the programming ideas of underlying parameters such as top and background values,maximum and minimum values and the calculation method of other parameters from the underlying parameters were given.2.In this thesis,the creation method of eye diagram and measurement algorithm of the parameters such as ocular,eye width,eye amplitude,extinction ratio were developed.The creation of eye graph was achieved through combining with the formation of eye principle,as well as the measurement algorithm and programming ideas were determined through combining with the statistical thinking and the significance of the parameters.We add extinction ratio measurement in this module which can be applied in the optical communication field.3.In this thesis,the definition and creation method of eye diagram template in the ITU-T G.957 standard for STM-1 and STM-4 were researched,and then the architecture and function of the software system were discussed in detail.In addition,I attempt to add a function button to the eye diagram template,users can close it when they do not need template comparison.4.In this thesis,the conception of SDH frame structure and the significance of software clock recovery were studied.The PLL principle and mathematical model were analyzed,also the method for clock was identified.Finally,we will introduce the process of software design and conduct a feasibility judgement.