Digital Oscilloscopes, High-speed Real-time Data Processing Technology

Digital oscilloscope is a high-performance oscilloscope which is created by a series of technologies ,such as a set of data acquisition, A / D conversion, software programming and so on . It is able to provide users with waveform trigger, storage, display, measurement, waveform data analysis and processing functions. A good digital oscilloscope, not only have a high sampling rate, to be able to rebuild the original signal very well, but also need to have a strong ability to analyze the waveform. To achieve the above these,it is have to rely on digital signal processing technology's use in the digital oscilloscope. With the gradual increase in demand of digital oscilloscope performance, DSP processor's computing speed gradually can not meet the requirements. Therefore, hardware-based high-speed data processing become a new research direction of digital oscilloscope .This paper describes using the FPGA to implement digital signal processing techniques ,such as the interpolation algorithm, FFT algorithm, as well as the use of DSP technology to correct errors.For digital oscilloscopes, Interpolation algorithm is a digital signal processing technology which is must be used, in previous studies, Interpolation algorithm is achieved with the DSP processor, the speed gradually does not meet the requirements. Interpolation algorithm, including sinusoidal interpolation, linear interpolation and so on. In this paper, the sine interpolation is used to achieve,which is based on the low-pass filter, according to time-base files of the digital oscilloscope to determine the need for interpolation of multiple,then according to the formula of sine interpolation to calculate the coefficient,using the rich resources of FPGA ,such as multipliers and adder to programming.In the digital oscilloscope, mainly use FFT algorithm to calculate the wave spectrum, to facilitate analysis of the details of the waveform. This paper is designed for 8-bit precision of 1024 sample points FFT operation in the FPGA to achieve,because the efficiency of DSP processor operation is too low. The process of FFT algorithm designed in this paper as follows: First, set the port of FFT IP CORE which is built-in Xilinx's ISE software,generate code, and then join the ISE project, simulation, compared this results with the simulation results in Matlab,then analyzed.In order to meet the shortage of real-time sampling rate of domestic Digital oscilloscope, using a parallel time-interleaved sampling technique, using multi-chip relatively low sampling rate ADC parallel sampling together such a high sampling rate. However, because of technology and other factors, it will cause channel mismatch errors, such as offset error, gain error, time delay error. This paper presents a comprehensive correction method, three kinds of errors can be corrected at the same time, improve the overall performance of digital oscilloscope effectively .Because the research is lack of depth and breadth , there is a great distance between research results of the article and the international advanced level, Finally, the next step was prospected.