Development Of Multi-channel GHz Waveform Sampling System Based On DRS4

The high speed waveform digitization system is used to collect the output waveform of the particle detector so that the experimenters can obtain all the physical information carried by high-energy particles through the analysis of waveform.This technology has a wide application prospect in particle physics experiment,medical instrument,meteorology and other fields.The traditional waveform digitization system based on Flash Analog-to-Digital Converter(FADC)has been widely used in particle physics experiments,but with the continuous improvement of sampling rate and resolution,the power consumption of FADC is higher and higher,and the single-channel price is very expensive.Therefore,scientists propose a waveform digitalization technology route based on Switch-Capacitor Arrays(SCA)+ slow and high resolution ADC.This technology route has great advantages in power consumption and cost,and is one of the main routes for the future development of waveform digitalization technology.At present,the research and application of waveform digitization technology based on SCA have been carried out at home and abroad.The research and design of SCA chip in foreign countries started earlier,and a number of mature commercial-grade SCA ASIC(Application Specific Integrated Circuit)chip design in China started late.At present,the research mainly focuses on the application of DRS4(Domino Ring Sampler)chip launched by PSI(Paul Scherrer Institute).In this paper,a set of 4-channel waveform digital system with low power consumption,high resolution and high sampling rate is improved by investigating the previous application design of DRS4,and the system is measured.The main work of this paper is as follows:(1)This paper introduces the principle of high-speed waveform digitization technology and its application in particle physics experiments,compares the principle,advantages and disadvantages of two waveform digitization technology routes based on SCA+ADC and FADC,and determines that this paper takes SCA+ADC as the design direction.The structure,working principle and working mode of DRS4 chip are introduced in detail.(2)Investigate the waveform digitization system based on DRS4 designed by predecessors,and summarize the existing problems.1)The use of USB2.0 for data transmission limits the transmission distance;2)Without on-board data storage system,data will be transferred to the memory of the upper computer for storage,and a large amount of data will occupy the memory of the upper computer and reduce the processing speed.The solution is proposed: 1)DDR3 SDRAM(double-data-rate three synchronous dynamic random access memory)is designed as an on-board storage system.Advanced e Xtensible Interface-Direct Memory Access(AXI-DMA)is used to read and write data.The storage space is 8G-bit,and the maximum transmission rate is 1600 MHz.2)The Gigabit Ethernet interface is designed to transmit data to the upper computer by using the User Datagram Protocol(UDP)with the maximum transmission rate of 1Gbps.(3)Design the hardware circuit of waveform digitization system based on DRS4.The design includes: design front-end analog circuit to analyze and calculate the analog signal input of DRS4,design ADC circuit to digitize the output signal of DRS4,DDR3 SDRAM circuit for on-board data storage and Ethernet data transmission circuit;Design DAC(Digital to Analog Converter)circuit which provides reference level for signal correction,and realize the design and development of waveform digital system circuit board with EDA software.(4)The logical structure of the high-speed waveform digitization system based on DRS4 is according to the modular designed,the hardware language is used to configure DRS4,ADC,DAC,analog switch and other devices.FPGA(Field Programmable Gate Array)is used as the control core to implement data read and write of DDR3 SRDAM and high-speed data transmission with Ethernet UDP protocol.Using the bit machine program developed based on wx Widgets platform provided by PSI(Paul Scherrer Institute),hardware configuration and data processing and waveform reconstruction display are realized in the window interface.(5)Build the test platform of waveform digital system on the basis of the completion of hardware and logic design.The module function and system performance are tested,and the results show that: The waveform digitization system based on DRS4 has good operation stability,and the maximum sampling rate is up to5 GHz.The sinusoidal waveform of 200 MHz can be sampled and tested on the upper computer.After adding the correction algorithm,the channel noise is about 0.3m V,and the nonlinear error is less than 0.1%.