TDR脈沖源和采樣關(guān)鍵技術(shù)研究
發(fā)布時(shí)間：2018-10-26 21:10
【摘要】：TDR(Time Domain Reflectometry,也稱時(shí)域反射儀)是用于檢測PCB阻抗、線纜損壞與否的測量儀器。為了更好的在阻抗測量領(lǐng)域中發(fā)揮作用,急需提升該測量儀器的性能。TDR的性能體現(xiàn)在測試分辨率和系統(tǒng)帶寬,前者由系統(tǒng)上升時(shí)間決定,后者則受脈沖源和采樣系統(tǒng)共同決定。因此,脈沖源模塊和采樣系統(tǒng)是提升TDR性能的關(guān)鍵所在。本文研究內(nèi)容如下:1.分析了匹配傳輸、反射形成過程以及TDR的工作原理和方案設(shè)計(jì),并對TDR的關(guān)鍵技術(shù)進(jìn)行了分析。2.脈沖源的設(shè)計(jì)。脈沖源的難點(diǎn)在于其輸出脈沖既要有較快上升沿,又有要較小的頂部抖動(dòng)、振鈴等特點(diǎn)。本文給出了兩種脈沖設(shè)計(jì)方案。第一種是利用隧道二極管的隧道效應(yīng)對現(xiàn)有脈沖進(jìn)行調(diào)整,以得到上升沿較快的脈沖。第二種是利用SRD的阻抗變化特性,完成脈沖初步整形,再利用比較器的比較特性對脈沖繼續(xù)加速,由此得到超快脈沖。通過仿真比較可知,第二種方案得到的脈沖信號的上升沿更快、頂部平坦性更好。3.采樣系統(tǒng)中關(guān)鍵技術(shù)的研究。在差值采樣的基礎(chǔ)上,對差值采樣系統(tǒng)進(jìn)行研究并對其中的關(guān)鍵技術(shù)進(jìn)行了分析。本文設(shè)計(jì)了加減法電路配合功分器的方案對采樣過程中的旁通效應(yīng)進(jìn)行改善,經(jīng)過仿真與結(jié)果分析可知,旁通效應(yīng)得到一定的改善。本文給出了基于SRD和微帶線組合以及基于雪崩晶體管的兩種采樣脈沖設(shè)計(jì)方案。第一種方案的重點(diǎn)在于高幅值超快脈沖信號的產(chǎn)生及脈沖形成網(wǎng)絡(luò)的設(shè)計(jì)。第二種方案的重點(diǎn)在于雪崩工作狀態(tài)的設(shè)置及電路中各參數(shù)間的協(xié)調(diào)。經(jīng)過仿真與結(jié)果分析可知,第二種方案得到的采樣脈沖的有效底寬更窄、帶寬更高、對稱性更好。在論文的最后對脈沖源、采樣脈沖的設(shè)計(jì)方案進(jìn)行了電路設(shè)計(jì)與測試,并應(yīng)用在TDR中。經(jīng)測試可知,脈沖源的上升沿達(dá)到57ps,采樣脈沖有效底寬230ps左右,系統(tǒng)上升時(shí)間約為140ps,系統(tǒng)帶寬約為2.5GHz,提高了TDR的測試性能,工程應(yīng)用價(jià)值大。
[Abstract]:TDR (Time Domain Reflectometry, (time domain reflectometer) is used to detect PCB impedance, cable damage or not. In order to play a better role in the field of impedance measurement, it is urgent to improve the performance of the measuring instrument. The performance of the TDR is reflected in the measurement resolution and the system bandwidth, the former being determined by the system rise time. The latter is determined by both the pulse source and the sampling system. Therefore, pulse source module and sampling system are the key to improve TDR performance. The contents of this paper are as follows: 1. The matching transmission, reflection forming process, working principle and scheme design of TDR are analyzed, and the key technology of TDR is analyzed. 2. Pulse source design. The difficulty of pulse source is that the output pulse not only has fast rising edge, but also has the characteristics of small top jitter and ringing. Two pulse design schemes are presented in this paper. The first is to use the tunneling effect of the tunnel diode to adjust the existing pulse to obtain the fast rise edge pulse. The second is to use the impedance variation of SRD to complete the initial shaping of the pulse, and then to accelerate the pulse by using the comparator's comparison characteristics, and then to obtain the ultra-fast pulse. The simulation results show that the rising edge of the second scheme is faster and the flatness of the top is better. Research on key techniques in sampling system. On the basis of difference sampling, the differential sampling system is studied and the key technologies are analyzed. In this paper, the scheme of adding and subtracting circuit with power divider is designed to improve the bypass effect in the sampling process. Through simulation and analysis of the results, it can be seen that the bypass effect has been improved to a certain extent. In this paper, two sampling pulse design schemes based on SRD and microstrip line combination and avalanche transistor are presented. The first scheme focuses on the generation of high amplitude ultra-fast pulse signal and the design of pulse forming network. The second scheme focuses on the setting of avalanche working state and the coordination of the parameters in the circuit. The results of simulation and analysis show that the effective base width of the second scheme is narrower, the bandwidth is higher and the symmetry is better. At the end of the paper, the design scheme of pulse source and sampling pulse is designed and tested, and it is applied in TDR. The test results show that the rising edge of the pulse source is 57 pss, the sampling pulse effective bottom width 230ps is about, the rising time of the system is about 140 psand the system bandwidth is about 2.5 GHz, which improves the testing performance of TDR and has great engineering application value.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM934.7
，
本文編號：2296953
[Abstract]:TDR (Time Domain Reflectometry, (time domain reflectometer) is used to detect PCB impedance, cable damage or not. In order to play a better role in the field of impedance measurement, it is urgent to improve the performance of the measuring instrument. The performance of the TDR is reflected in the measurement resolution and the system bandwidth, the former being determined by the system rise time. The latter is determined by both the pulse source and the sampling system. Therefore, pulse source module and sampling system are the key to improve TDR performance. The contents of this paper are as follows: 1. The matching transmission, reflection forming process, working principle and scheme design of TDR are analyzed, and the key technology of TDR is analyzed. 2. Pulse source design. The difficulty of pulse source is that the output pulse not only has fast rising edge, but also has the characteristics of small top jitter and ringing. Two pulse design schemes are presented in this paper. The first is to use the tunneling effect of the tunnel diode to adjust the existing pulse to obtain the fast rise edge pulse. The second is to use the impedance variation of SRD to complete the initial shaping of the pulse, and then to accelerate the pulse by using the comparator's comparison characteristics, and then to obtain the ultra-fast pulse. The simulation results show that the rising edge of the second scheme is faster and the flatness of the top is better. Research on key techniques in sampling system. On the basis of difference sampling, the differential sampling system is studied and the key technologies are analyzed. In this paper, the scheme of adding and subtracting circuit with power divider is designed to improve the bypass effect in the sampling process. Through simulation and analysis of the results, it can be seen that the bypass effect has been improved to a certain extent. In this paper, two sampling pulse design schemes based on SRD and microstrip line combination and avalanche transistor are presented. The first scheme focuses on the generation of high amplitude ultra-fast pulse signal and the design of pulse forming network. The second scheme focuses on the setting of avalanche working state and the coordination of the parameters in the circuit. The results of simulation and analysis show that the effective base width of the second scheme is narrower, the bandwidth is higher and the symmetry is better. At the end of the paper, the design scheme of pulse source and sampling pulse is designed and tested, and it is applied in TDR. The test results show that the rising edge of the pulse source is 57 pss, the sampling pulse effective bottom width 230ps is about, the rising time of the system is about 140 psand the system bandwidth is about 2.5 GHz, which improves the testing performance of TDR and has great engineering application value.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM934.7
，
本文編號：2296953
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