基于DDS的扫频信号发生器

直接数字频率合成技术 (DirectDigitalSynthesis ,简单DDS)是近年来发展起来的一种新型信号合成技术。由于采用了全数字结构 ,它具有合成信号相对频带宽、频率转换时间短、频率分辨率高及合成信号相位连接等优点。介绍了DDS的基本原理 ,详细描述了DDS芯片AD70 0 8特点 ,并给出了基于AD70 0 8芯片的 5MHz扫频信号发生器。     

电路包络:一种微波电路稳态分析新方法

现代通信信号在射频载波上采用复杂的数字调制(如/4DQPSK,GMSK和QAM)以提高频谱效率。通用的两种仿真技术(时域积分法和谐波平衡法)不能对任意载波频率调制的通信系统进行有效的分析。介绍了可以填补这一空缺的仿真技术,并用该方法对二极管强非线性电路进行了分析。仿真结果表明这种仿真方法是有效的。     

Discrete Approach to PWL Analog Modeling in VHDL Environment

In this paper a discrete approach to analog modeling is presented. It is a functional-level, piecewise-linear (PWL) technique implemented in the VHDL environment. Since the models are based on some explicit formulas, fully behavioral architectural bodies have been proposed for them. Their most distinguishing features are discussed in detail. The models of practical circuits are illustrated with simulation results.     

天线充气系统分析研究

介绍天线充气系统在雷达天线系统中的重要作用 ,并通过分析比较 ,优选出适合雷达天馈系统的充气系统方案 ,并通过具体实例进行分析     

一种基于频率响应屏蔽技术的FIR滤波器设计新方法

提出了一种设计高效窄过渡带宽FIR滤波器的新方法。该方法以传统的频率响应屏蔽(FRM)方法为基础,通过选择特定的原型滤波器来降低合成的数字FIR滤波器的复杂度。本文研究了该方法的原理、实现结构和设计方法,并通过设计实例证明了此方法的有效性。     

A curve fitting signal processing scheme for a white-light interferometric system with a synthetic source

A white-light interferometric system, which comprises two Michelson interferometers linked by a 100 μm diameter core multimode step index fibre has been investigated, where a signal processing scheme, using curve fitting, has been introduced to suppress the noise induced in the system. The theoretical resolution of such a sensor with the use of an appropriate curve fitting signal processing scheme has been discussed. The experimental results obtained show the short term repeatability (to three standard deviations) to be better than 5 nm after signal processing, under conditions where the fibre is constantly vibrated in a known and reproducible way.     

脉冲多普勒雷达作为导航传感器的应用研究

分析了采用脉冲多普勒雷达作为导航传感器的可能，并说明了将这种雷达用作多普勒导航传感器的两种方法。     

一种适合多媒体处理的新型芯片

介绍ＭＭＸ技术的基本内容及带有ＭＭＸ技术的微处理器，以ＭＭＸ技术在视频会议系统上的应用为例，侧重分析ＭＭＸ技术给多媒体与通信应用带来的性能改善，并对ＭＭＸ技术的应用及发展前景进行探讨。     

一种基于DSP技术的目标自动录取设备

介绍了一种基于多片DSP芯片ADSP-21060的小型化可编程目标自动录取设备的设计方法，给出硬件设计框图及软件流程图，用此方法设计的自动录取设备具有功能灵活、体积小、可靠性高、适应性好等特点。     

Suppression of Sea-Ice Clutter Observed by a Millimeter Wave Radar Using a New Log-Weibull/CFAR System

Sea-ice clutter was measured using a millimeter wave radar with frequency of 34.860GHz, beamwidth of 0.25° and pulse length of 30ns. To determine the sea-ice clutter amplitude statistics, we investigated the log-normal, Weibull, log-Weibull and K-distributions using the Akaike Information Criterion (AIC), which is more rigorous fit of the distribution to the data than the least-squares method. It is shown that the amplitude of sea-ice clutter obeys the log-Weibull distribution with shape parameters of 2.36 to 2.93 for both entire data and data within the beam width of an antenna. We propose a new log-Weibull/CFAR system uses a modified cell-averaging LOG/CFAR system. It is found that this log-Weibull/CFAR procedure is effective for suppression of sea-ice clutter and detection of target.