共查询到20条相似文献,搜索用时 46 毫秒
1.
基于单片机与FPGA的等精度频率计设计 总被引:1,自引:0,他引:1
根据等精度测频原理,利用单片机与FPGA结合设计等精度数字频率计。待测频率信号经过整形放大后输入到FPGA,单片机控制FPGA通过内部脉冲计数器对待测信号和标准信号源同时计数,单片机读回测频数据后,经运算处理后显示。等精度频率计测频精度高,且精度不随频率的变化而变化。单片机与FPGA结合,测频速度快,范围宽,可靠性高。 相似文献
2.
3.
4.
5.
摘要:脉内载频特征是雷达被动信号分选的关键参数,为提高雷达信号载频特征提取精度,引入相位测频法。
利用希尔伯特变换将原始信号转换为复信号,进而求取各采样点对应的相位及瞬时频率,对各点瞬时频率取均值作
为信号载频特征。将相位测频法与傅里叶变换法、计数法进行了仿真对比,结果表明:相位测频法在低载频、短脉
宽的情况下测频精确度优于傅里叶变换法和计数法。因此相位测频法应用于雷达载频特征提取,能有效提高测频精
度和稳定性,为复杂背景下雷达被动信号分选与识别提供支持与保障。 相似文献
6.
7.
8.
9.
10.
11.
Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design. 相似文献
12.
By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux (kernel version 2.6.11 ) is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development. 相似文献
13.
Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective. 相似文献
14.
A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same. 相似文献
15.
The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment. 相似文献
16.
Manfred Held 《兵工学报(英文版)》2006,2(1):22-32
First the different anti-tank mines laying possibilities are shortly summarized: hand emplaced, with mine layers, ground or helicopter relatively topographical well defined, and with cluster systems of projectiles, rockets and aircraft dispensers. Then examples of the three generations of anti-tank mines are presented:Ⅰ generation: detonating only beneath the track; Ⅱ generation: detonating beneath the track and belly; Ⅲ generation: mines with off-route actions. Weight and cost comparisons are strongly favoring the off-route Ⅲ-generation mines. 相似文献
17.
A static finite element analysis (FEA) of an impulsive controller section is presented. The boundary condition and a part of the loads are applied. Considering the grades of the stress around the holes being large, the dense grids are adjusted accordingly. Four cases with different loads are compared, thus the influences of different loads on the section are analyzed. Numerical results show that the maximum stress of the section is lower than the strength limit of the material, and the section will not be broken with the static loads. 相似文献
18.
From the view point of launch safety caused by fracture of propellant charge, this paper points out that the safety criterion of pressure wave is inadequate to evaluate the launch safety of propellant charge based on the initial negative differential pressure and sensitivity tests. Generally, the maximum barrel pressure does not depend upon the intensity of pressure wave correspondingly. The pressure wave intensity can not describe the fracture degree of propellant charge in chamber and reflect the mechanical environment of propellant charge fracturing exactly and wholly. The evaluation criterion for launch safety of propellant charge should be built on the basis of depicting the fracture degree of propellant bed. 相似文献
19.
The polycyclic nitramine hexanitrohexaazaisowurtane(HNIW) is a compound of high energy density. HNIW can replace 1, 3, 5-trinitro-1, 3, 5-triazacyclohexane(RDX) or HMX, hut its toxicity is unknown. In this paper, HNIW, hexabenzylhexaazaisowurtzitane (HBIW), tetraacetyldibenzulhexaazaisowurtzitane (TADBIW), tetraacetyldiformylhexaazaisowurtzitane(TADFIW) and tetraacetylhexaazaisowurtzitane(TAIW), which are intermediates of the synthesis of the HNIW, were selected as the tested objects in acute toxicity test, acute eye stimulation test and skin irritation test according to the standards of "chemical product testing method-401 : acute oral toxicity test", "chemical product testing means-405: acute eye irritation/corrosion test" and "chemical product testing means-404: acute dermal irritation/corrosion test" of National Circumstance Protect Bureau. The results show that all of the five objects have no toxicity, no stimulation to eye and skin under the tested conditions. 相似文献
20.
Dynamic Simulation for Missile Erection System 总被引:1,自引:0,他引:1
In order to study the dynamic characteristics of the missile erection system, it can be considered as a rigid-flexible coupling multi-body system. Firstly, the actual system is abstracted as an equal and simplified one and then the forces applied to it are analyzed. Secondly, the rigid-flexible coupling dynamic simulation for erection system is accomplished by use of the system simulation software, for example Pro/E, ADAMS, ANSYS, MATLAB/Simulink, etc. Finally, having the aid of simulation results, the kinetic and dynamic characteristics of the flexible bodies in erection system are analyzed.The simulation considering the erection system as a rigid-flexible coupling system can provide valuable results to the research of its kinetic, dynamic and vibrational characteristics. 相似文献