Research On The Broadband Seamless Acquisition And Its Application In Digital Storage Oscilloscope

Presently, the modern electronic signal reveals its features of complexity and diversity. Particularly, because of the blossom of the broadband and non-stationary property, it's getting hard for the traditional frequency-domain testing instruments, which are dominated by the frequency sweep technology, to satisfy the seamless tests requirements of broadband and transient signal. With the growth of the ADC sampling bandwidth and the DSP theory and techniques becoming more sophisticated, the time-domain test based on real-time sampling, such as digital storage oscilloscope, is emerging to the mainstream of electronic test development, and also gestating the important transformation on electronic instrumentation systems.However, the extreme dependence on sampling rate and the rapidly inflated amount of information processing already become the time-domain test's bottleneck, and it greatly restricts the broadband time-domain test equipment's development and application. It is also the major problem in the research area. Taking the technology of broadband seamless acquiration as the core, and under the support of National Natural Science Fundation of China(No. 60827001) and aiming for the technology such as the architecture of the seamless acquiration system, the composition method of broadband digital storage oscilloscope with the character of seamless acquiration and the several key technologies'real-time issues in digital oscilloscope which affect the performace of seamless acquiration, this dissertation carried out following researches.(1)Research on Seamless Acquiration and Waveform Capture Rate This chapter introduced the basic concept of waveform capture rate, and did some researches on the relationship between the waveform capture rate and the dead time in the view of informatics and derived the information entropy of accidental events capture by time-domain testing instruments, and discussed the wavform capture rate acting as an important role in the system of data acquiration, and from this, put forward the concept of seamless acquiration. Finally it introduced the approaches to test the waveform capture rate from the external characteristics.(2)Constitution method of seamless acquisition system On account of the defects of the series design of traditional time-domain testing instruments, this chapter put forward the composition method for parallel design data acquisition system and went further on the mathematical model of the designs, and performed the detailed calculation and analysis on the waveform capture rate of the design. On this basis, it proposed the design method of the seamless acquiration architecture and introduced the improved waveform parallel mapping structure through the assembly line process technology, and then it deduced the basic conditions which the structure of the seamless acquiration should meet. At last, the validity and engineering application have been verified.(3)Digital Storage Oscilloscope Technology Based on Seamless Acquisition This chapter firstly studied the basic waveform mapping technology in digital three-dimension oscilloscope. And then, combining it with the seamless acquiration architecture introduced in the last chapter, it inroduced the application in the system of massive parallel sampling, and derived the mathematical model and analyzed the mapping efficiency. Finally, it also studied the interpolation method of one advanced poly-phase filter under fast time-base grade, and put forward the base model of seamless acquisition during interpolation, and analyzed the waveform process and mapping efficiency.(4)Parallel Sampling Real-Time Correcting Method This chapter researched on the real-time correcting method for the non-uniform sampling deviation caused by the interleaved parallel sampling. It suggested adopting Normalization Algorithm to correct the non-uniform deviation of system amplitude and low-pass filter method or time delay estimation method to correct the non-uniform deviation of system time. At last, the validity of this method was verified in the experiment.(5)Bandwidth Filter Enhancement Technology This chapter studied the digital post-treatment method that can improve the analog bandwidth of digital oscilloscope, and discussed the fundamental principle of bandwidth enhancement technology and how to design the filter. Through some experiments, the algorithm can successfully achieve the goal of increasing 20% test bandwidth while limiting the overshoot within 5%.(6)Waveform Details Capturing and Processing Technique This chapter raised solution of the high-speed data flow depth storage technology, and aimed at the problem of the efficiency of processing the large volume data in the high-speed data flow depth storage process, we adopted the eigenvalue detection technology, and derived the mathematical model of this technology and analyzed fast processing efficiency.(7)Parallel Sampling Trigger Synchronous Technology This chapter puts forward a synchronous trigger method (time stretching circuit test method) which is irrelevant to the features of input signal to solve the trigger jitter problem happens during the parallel sampling, and analyzed the deviation model.(8)Application of Broadband Seamless Acquiration Oscilloscope This chapter introduced design method of a broadband seamless acquiration oscilloscope, including design objectives, the overall scheme and work flow, and accessed the results of the experimental testing and analysis.