Applied Mechanics and Materials Vols. 602-605

Abstract: As the measuring equipment of the navigation receivers, high precision pseudorange signal is generated by navigation signal simulator. Pseudorange error is mainly from modeling error in high dynamic scenarios, but it is mainly from phase quantization error of digital implementation process in high precision scenarios of evaluating receiver’s pseudorange accuracy. Is this paper, according to the implementation principle of carrier and code DDS, the causes of the phase quantization error is analyzed and the pseudorange error formula is derived and the simulation results are given. Analysis and simulation results show that phase critter originated by carry phase truncation effects measurement result of zero value and cannot be ignored. The conclusion can guide the design of navigation signal simulator.

Abstract: A design of capacitor-coupled ECG test system is introduced here. The extremely weak ECG signal was picked up with capacitor coupling sensor, and was then buffered, filtered and magnified to fit the requirement of analog digital converter. The measured data was then converted and processed by a microcontroller. The ECG signal can be recovered and stored, analyzed by intelligent terminal. The test shows that this method is applicable and would be used widely.

Abstract: ADS8364 is a sixteen-bit parallel output that is sampling and conversion at the same time by six channels. It is a kind of high-precision chip sampling in power. ADS8364 is introduced which combined with practical application of DSP on the attitude and heading reference. ADS8364 which can carry out data collection of six channels is used in the attitude and heading reference for data collection of MEMS sensor of inertial. The data are transmitting to DSP which could complete processing of data and estimate of attitude. By analyzing the results of examination, the precision of MEMS gyroscope’s data which are collected by ADS8364 synchronously could satisfy the request of the attitude and heading reference.

Abstract: In this paper, we use the embedded theory and wavelet algorithm to improve image coding, and get a new optimization algorithm of track and field image, and establish the wavelet reconstruction mathematical model of image optimization. In order to verify the effectiveness and reliability of the wavelet reconstruction algorithm, this paper uses computer embedded PLC control system and 317-2 PN/DP special CPU to establish the optimization system of track and field path, and debug a program by using Step7 software, which realizes the calculation function of embedded system. Finally, this paper does wavelet reconstruction on real time image, we obtain the reconstruction wavelet optimal path, and output it in the form of digital image, and use the drawing function to realize re-draw function of image, finally we get the route optimization figure of track and field teaching. It provides a new method for computer teaching process.

Abstract: With the improvement of living standards, people's lives have become increasingly dependent on water heater facility. Fast electric water heater is environmental, economic, more convenient than storage water heaters. Compared with gas water heaters, it’s more safe and energy-efficient . This article will introduce a safe and efficient hot-water heaters, through reasonable optimizing its structure so that it can heat the water in the 3s, but by deepening the circuit schematic to ensure the safety function.

Abstract: This paper shows the research on hardware random number generator (HRNG). As truly random numbers are strongly required in encryption and computer simulation areas, developing a simple and inexpensive HRNG has significant value. The whole system is divided into the noise generating module and the processing module. After the numbers are generated, a randomness test has been carried out which indicates that the random numbers generated are truly random. It is concluded that the final product of this HRNG meets the requirements of the objectives.

Abstract: To protect the security of critical data and application system, generally, many companies or departments use a parallel way of intranet and internet. Because every kind of security technology has its limitations, traditional security products such as firewall, VPN, data encryption, intrusion detection and network vulnerability scanning can not completely solve various security problems in information exchange between different networks. It is not able to meet all the security needs of critical networks and security data with the general products only. The way of data exchange of most of the existing products of "GAP" is mainly logic isolation .This paper describes a design and implementation of a hot switch circuit card in way of physical isolation .The data exchange mode of this circuit card is a half-duplex which can physically completely isolate intranet and internet. Through functional test and performance test, we can draw a conclusion that the circuit card can effectively achieve our demand of data exchange between different networks.

Abstract: In this paper, cross metal patches are inserted inside the conventional rectangular microstrip antenna, and thus it can work at two frequencies. The finite difference time domain (FDTD) method is selected to study effect of this left-handed metamaterial with near-zero-index of refraction. Compared with conventional rectangular microstrip antenna, effect of near-zero-index from positive and negative on conventional rectangular microstrip antenna are studied. Simulation results show this antenna works at two frequencies. Compared with conventional microstrip antenna, near-zero-index can improve antenna’s gain obviously.

Abstract: With the rapid development of communication technology, software radio technology had become more and more widespread. This paper firstly studied the software radio technology, described its key ideas and main technologies, and then analyzed the broadband RF front-end as an important component of the software radio technology, designed the architecture of RF front-end. The experiment result proved it could improve the quality of signal effectively.

Abstract: The active and reactive power decoupling control of photovoltaic system is analyzed in this paper. The DC-DC and DC-AC two level photovoltaic inverter model are built on the RTDS. A new type LVRT control strategy about photovoltaic system is proposed. In the symmetrical grid drop fault case, photovoltaic system output reactive power to support the grid voltage recovering and save reactive power equipment. The feasibility and effectiveness of the control strategy is verified by simulation and experiment on the RTDS.