The paper proposes a novel approach for fine frequency synchronization of OFDM syn- chronization systems in multi-path channels. Maximum Likelihood (ML) function of frequency offsets including integral and decimal par...The paper proposes a novel approach for fine frequency synchronization of OFDM syn- chronization systems in multi-path channels. Maximum Likelihood (ML) function of frequency offsets including integral and decimal parts in frequency domain is developed according to the law of great number to eliminate the noise impact of the signal. When the timing delay close to the actual time, the proposed function produces a deep valley indicating frequency offset when large Valley-Square- Error (VSE) appears. Coarse timing offset can also be detected when function’s Valley-Square-Error (VSE) is maximized. Simulation results shows that the proposed algorithm gives very robust estimation of frequency offset, and a coarse timing offset estimation.展开更多
In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Are...In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Area Network） could be communicated. This article mainly introduced the VLAN classification method inter-VLAN data communication technology, and explained in detail with two simple examples the concrete configure method of the communication between the same cross-switch VLAN traffic and inter-VLAN.展开更多
The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with...The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with other intelligent nodes of the reversing radar. The experimental results show that, the design can achieve the expected technical indicators design, measurement precision and the reliability is high, which has certain guiding significance in the design of the car reversing radar, has wide application prospect and practical significance in the function of the extended CAN bus communication messages design and automotive CAN network.展开更多
NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmi...NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmitted in the network. Without automatic configuration mechanism, the stability and flexibility of the synchronization network built upon NTP protocol are not satisfying. P2P’s resource discovery mechanism is used to look for time sources in a synchronization network, and according to the network environment and node’s quality, the synchronization network is constructed dynamically.展开更多
In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize...In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize data acquisition and remote transmission. The test results show that the system can support 16 line array CCD test node to measure the micro deformation of the one- dimensional, the CCD data transmission rate is 3200 frames/s, node data transmission distance is greater than 200 m, and measurement accuracy is 500 micron.展开更多
文摘The paper proposes a novel approach for fine frequency synchronization of OFDM syn- chronization systems in multi-path channels. Maximum Likelihood (ML) function of frequency offsets including integral and decimal parts in frequency domain is developed according to the law of great number to eliminate the noise impact of the signal. When the timing delay close to the actual time, the proposed function produces a deep valley indicating frequency offset when large Valley-Square- Error (VSE) appears. Coarse timing offset can also be detected when function’s Valley-Square-Error (VSE) is maximized. Simulation results shows that the proposed algorithm gives very robust estimation of frequency offset, and a coarse timing offset estimation.
文摘In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Area Network） could be communicated. This article mainly introduced the VLAN classification method inter-VLAN data communication technology, and explained in detail with two simple examples the concrete configure method of the communication between the same cross-switch VLAN traffic and inter-VLAN.
文摘The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with other intelligent nodes of the reversing radar. The experimental results show that, the design can achieve the expected technical indicators design, measurement precision and the reliability is high, which has certain guiding significance in the design of the car reversing radar, has wide application prospect and practical significance in the function of the extended CAN bus communication messages design and automotive CAN network.
文摘NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmitted in the network. Without automatic configuration mechanism, the stability and flexibility of the synchronization network built upon NTP protocol are not satisfying. P2P’s resource discovery mechanism is used to look for time sources in a synchronization network, and according to the network environment and node’s quality, the synchronization network is constructed dynamically.
文摘In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize data acquisition and remote transmission. The test results show that the system can support 16 line array CCD test node to measure the micro deformation of the one- dimensional, the CCD data transmission rate is 3200 frames/s, node data transmission distance is greater than 200 m, and measurement accuracy is 500 micron.
