Research On The Application Of Virtual Instrument Technology In High Speed DAC Test

The performance of DAC is a key factor to evaluate the performance of modern electronic equipment,due to the high speed DAC conversion rate greater than 50 MHz to more quickly for digital analog conversion,which is wi dely used in modern electronic equipment,how to quickly and accurately test and evaluate the performance of high speed DAC is very important.The field of traditional semiconductor test instrument is applied to rapid test automation needs exposed the limitations of manual operation and independent using,but the virtual instrument as a new stage of development of the measuring instrument,the characteristics of bus mode and multi instrument modular combination is very conducive to the rapid DAC test automation,it has very important practical significance to the development of the high speed DAC testing technology.This paper studied the test technology and test method of high speed DAC based on the virtual instrument,the key technology of high speed DAC t est control process is improved,at the end of the high-speed DAC test system based on virtual instrument is designed.Firstly,this paper analyzes the specific steps of high speed DAC test sequence control,introduces the abnormal situation of high speed DAC often appears,proposes design ideas of granular computing based on sequence control,a high speed DAC test of granular computing hierarchy,using weighted size K improved near neighbor classification algorithm to classify the test results,finally,the sequential control algorithm based on granular computing is implemented and verified on the virtual instr ument software platform Lab VIEW.Secondly,this paper analyzes the main sources of static error of high-speed DAC,and compares several commonly used static input digital input code selection methods.On the basis of the main transition state test method,we take the anti-code test,which enhance the high digital code combination,and the three-parameter sine wave least squares fitting method is applie d to the signal and noise distortion ratio SINAD and the effective bit number ENOB.Thirdly,the overall design scheme of high speed DAC test system based on virtual instrument is identified,a test system hardware platform is built,the test board of the main chip test circuit,clock circuit,power supply and small signal acquisition with amplifying circuit and interface circuit design process are introduced,the laminated structure of PCB test board is determined,signal integrity analysis of high speed PCB test board is carried out,the analog output signal line matched termination resistor,through the plane harmonic analysis of adding decoupling capacitors in power distribution system,and the high speed DAC test system software is designed.Finally,on the hardware platform and software platform of high speed DAC test system based on virtual instrument,the static and dynamic parameters of high speed DAC samples are tested,it verifies the accuracy and practicability of control algorithm and system design of high-speed DAC test system based on virtual instrument.