In order to improve the accuracy of cable fault position location at a low cost and make the testing results intuitive, a cable fault detector based on wave form reconstruction is designed. In this detector, the cable...In order to improve the accuracy of cable fault position location at a low cost and make the testing results intuitive, a cable fault detector based on wave form reconstruction is designed. In this detector, the cable fault position is located based on the time-domain pulse reflection （TDR） principle. A pulse waveform is injected in the tested cable, and a high-speed comparator with changeable reference voltages is used to binarize the test pulse waveform to a binary sequence on a certain voltage. Through scanning the reference voltage in a full voltage range, multi-sequences are acquired to reconstruct the pulse waveform transmission in the cable, and then the pulse attenuation feature, electrical open circuit fault, electrical short circuit fault, and the fault position of the cable are diagnosed. Experimental results show that the designed cable fault detector can determine the fault type and its position of the cable being tested, and the testing results are intuitive.展开更多
In Direct Sequence Code Division Multiple Access (DS-CDMA) systems,the chip wave-form affects the implementation,system bandwidth,envelope uniformity,eye pattern and Multiple user Access Interference (MAI). In this pa...In Direct Sequence Code Division Multiple Access (DS-CDMA) systems,the chip wave-form affects the implementation,system bandwidth,envelope uniformity,eye pattern and Multiple user Access Interference (MAI). In this paper,based on an elementary density function of a second order polynomial,a class of second order continuity pulses is proposed. From this class of pulses,we can find some members having faster decaying rate,bigger eye opening,more uniform envelope and stronger anti-MAI capability than the Nyquist waveform. The normalized-bandwidth-pulse-shape-factor product,the decaying rate of the tail of the time waveform,the opening of the eye diagram,and the envelope uniformity of the second order continuity pulses are addressed in the paper that provide the basic information for the selection of the chip pulse for CDMA systems.展开更多
LabVIEW software is a very programmable tool, which can be easily retrofitted and customized to build new aspects of control and database monitoring systems for working with electrical devices. In an instructional env...LabVIEW software is a very programmable tool, which can be easily retrofitted and customized to build new aspects of control and database monitoring systems for working with electrical devices. In an instructional environment, the basic LabVIEW software processes provide simulation model of virtual sensors and their associated acceleration output from virtual motion input. This simulation can be used as part of an inclusive perception academic training system for engineering programs. Three virtual accelerometers were used to demonstrate the utility of simulating the acceleration force and vibration principles. A new LabVIEW front panel was developed to represent the sum of the simulation forces acting on each of the 3-axis semi-accelerometers. Thus, raw data strings of the 3-axis semi-accelerometers could be input as simulated real data and analyzed for time and the x, y, z-axis coordinate values. The toolkit of the LabVIEW platform is easy to implement, so engineers and scientists, who are very interested in knowing recent applications of the modem technology and the impact of its development processes, could be able to recognize the LabVIEW toolkits structure optimally, have a comprehensive practice with it and possess an extensive concept of the analysis techniques of this engineering language. Completely, the platform can also be quickly reconfigured to meet any specific laboratory technical requirements. So, this simulation study is underpinning of the accelerated coordinates understanding and has also been exclusive to create a virtual and vital acceleration application via the LabVIEW driver software.展开更多
基金The National Natural Science Foundation of China(No.61240032)the Natural Science Foundation of Jiangsu Province(No.BK2012560)+1 种基金the College Scientific and Technological Achievements Transformation Promotion Project of Jiangsu Province(No.JH-05)the Science and Technology Support Program of Jiangsu Province(No.BE2012740)
文摘In order to improve the accuracy of cable fault position location at a low cost and make the testing results intuitive, a cable fault detector based on wave form reconstruction is designed. In this detector, the cable fault position is located based on the time-domain pulse reflection （TDR） principle. A pulse waveform is injected in the tested cable, and a high-speed comparator with changeable reference voltages is used to binarize the test pulse waveform to a binary sequence on a certain voltage. Through scanning the reference voltage in a full voltage range, multi-sequences are acquired to reconstruct the pulse waveform transmission in the cable, and then the pulse attenuation feature, electrical open circuit fault, electrical short circuit fault, and the fault position of the cable are diagnosed. Experimental results show that the designed cable fault detector can determine the fault type and its position of the cable being tested, and the testing results are intuitive.
基金Supported by University Natural Science Research Pro-ject of Jiangsu (No.03KJB510088)National Natural Science Foundation of China (No.60572130).
文摘In Direct Sequence Code Division Multiple Access (DS-CDMA) systems,the chip wave-form affects the implementation,system bandwidth,envelope uniformity,eye pattern and Multiple user Access Interference (MAI). In this paper,based on an elementary density function of a second order polynomial,a class of second order continuity pulses is proposed. From this class of pulses,we can find some members having faster decaying rate,bigger eye opening,more uniform envelope and stronger anti-MAI capability than the Nyquist waveform. The normalized-bandwidth-pulse-shape-factor product,the decaying rate of the tail of the time waveform,the opening of the eye diagram,and the envelope uniformity of the second order continuity pulses are addressed in the paper that provide the basic information for the selection of the chip pulse for CDMA systems.
文摘LabVIEW software is a very programmable tool, which can be easily retrofitted and customized to build new aspects of control and database monitoring systems for working with electrical devices. In an instructional environment, the basic LabVIEW software processes provide simulation model of virtual sensors and their associated acceleration output from virtual motion input. This simulation can be used as part of an inclusive perception academic training system for engineering programs. Three virtual accelerometers were used to demonstrate the utility of simulating the acceleration force and vibration principles. A new LabVIEW front panel was developed to represent the sum of the simulation forces acting on each of the 3-axis semi-accelerometers. Thus, raw data strings of the 3-axis semi-accelerometers could be input as simulated real data and analyzed for time and the x, y, z-axis coordinate values. The toolkit of the LabVIEW platform is easy to implement, so engineers and scientists, who are very interested in knowing recent applications of the modem technology and the impact of its development processes, could be able to recognize the LabVIEW toolkits structure optimally, have a comprehensive practice with it and possess an extensive concept of the analysis techniques of this engineering language. Completely, the platform can also be quickly reconfigured to meet any specific laboratory technical requirements. So, this simulation study is underpinning of the accelerated coordinates understanding and has also been exclusive to create a virtual and vital acceleration application via the LabVIEW driver software.
