The Design Of Acquisition And Storage Module Of 5GSPS Oscilloscope

As an important electronic measuring instrument, oscilloscope which has been compared to the “eyes of engineers” plays an important role in the field of automatic test. PXI module is a digital storage oscilloscope based on PXI interface. It has the characteristics of both digital oscilloscope and PXI modular instrument. At the same time, it is widely used in the test system based on PXI bus.With the development of electronic technology, the complexity of electrical signal and the requirement of the index of the oscilloscope is also increasing. At present, it is difficult for the PXI oscilloscope module to meet the requirements of high precision measurement in China. Therefore, it is very important to develop PXI oscilloscope with high sampling rate and large storage depth. In this paper, the design of the acquisition and storage module of 5 GSPS oscilloscope is based on PXI oscilloscope platform, and also it will introduce the 5 GSPS real-time sampling rate, 200 GSPS equivalent sampling rate and the design of 256MB/CH memory depth circuit. The work mainly includes following several parts:(1)The design of high speed data acquisition unit. In this part, it will mainly introduce 5GSPS high speed sampling circuit, real-time sampling data receiving and caching and random equivalent sampling circuit. Firstly, it will propose the design scheme of data acquisition unit in Chapter 2.Then,it will elaborate the realization of the 5 GSPS high-speed sampling circuit, and also analyze how to realize the high-speed data acquisition and buffer, while focusing on the analysis of how the random equivalent sampling technology realize 200 GSPS equivalent sampling rate.(2)The design of data storage unit. The main research of this part includes the design of DDR2 SDRAM storage circuit, the design of DDR2 controller based on the IP core, the design of cross clock domain data processing and storage circuit control logic. First, it will put forward the design scheme of data storage unit in the second chapter, and then it will specifically discuss the DDR2 SDRAM memory circuit design and DDR2 SDRAM controller design based on IP core in the fourth chapter. At the same time, it will give a detailed analysis of the problem existing in the local end signal timing of DDR2 controller and the cross clock domain of data transmission. Finally, according to the analysis of the actual situation, it will design the storage circuit control logic and guarantee seamless data transmission.Finally, through the test, the design of the 5GSPS oscilloscope acquisition and storage module has reached the advanced level of the same type of products.