数字调频广播激励器原理与分析

介绍了数字调频广播发射机的优点,重点介绍了数字调频广播激励器的基本原理和各模块的构成原理及基本功能。数字调频广播的出现,是模拟调频广播重新走向辉煌的标志。他实现了人机对话、实时监控等智能化的功能,使用户更容易接受和使用。     

Chirped AM激光雷达中线性调频信号的产生

线性调频强度调制(Chirped AM)激光雷达将微波雷达中调频测距原理巧妙地应用于激光雷达,用一个线性调频的射频副载波调制激光输出强度.介绍了FM测距的基本数学原理,及激光雷达系统的基本构成和工作原理.在分析对比本体制激光雷达中一项关键技术一一线性调频信号产生几种实现方法的基础上,依据直接数字频率合成和正交调制技术,提出了一种宽带线性调频信号产生方案.介绍了信号发生系统的基本结构以及工作原理,探讨了系统实现的关键技术、技术难点及改进办法.     

线性调频信号和噪声调频信号性能对比分析

介绍了线性调频信号、噪声调频信号和匹配滤波的原理,对线性调频信号和噪声调频信号进行了时频域计算机仿真,并对两种信号加窗前后脉冲压缩的主副比、主瓣展宽等进行了对比分析,总结了两种调频信号的适用性.     

调频发射机N+1自动切换控制系统设计

探讨了调频发射机实现N 1自动切换控制系统的设计原理、技术难点和解决办法,简要介绍了吉兆调频5 1自动切换控制系统的一个应用实例.     

发展调频同步广播之浅见

通过简单介绍调频同步广播的原理及特点 ,论述了在青海省发展调频同步广播的必要性。     

小型调频广播发射机的工作原理与系统建设

主要以300W调频广播发射为例,阐述了发射机、音频处理器、发射机自动监测仪、音频幅度监测仪、监听系统和稳压电源的工作原理。并介绍了调频发射机的发射系统方案与建设。     

周口广播电视台调频广播发射机智能化N＋1系统

本文介绍了调频广播发射机N＋1系统的工作原理,以周口广播电视台发射中心调频广播4＋1系统为例,详细介绍了调频广播N＋1系统的实现及智能控制的实施方案.     

多种雷达体制在测距(测高)和测速方面的应用分析

本文结合实际全面介绍了锯齿波调频、正弦波调频、线性调频、伪随机码调相、多频连续波等多种雷达体制在测距(测高)和测速方面的应用,对其中关键技术要点作了较为详细的论述,通过分析其原理,比较了各自的优点和不足,给出了相关的应用领域。     

小型调频广播发射的工作原理与建设

主要以300 W调频广播发射为例,阐述了发射机、音频处理器、发射机自动监测仪、音频幅度监测仪、监听系统和稳压电源的工作原理,并介绍了调频发射机的发射系统方案与建设.     

哈密调频同步广播的设计与实施

本文分析了调频同步广播覆盖技术的特点和发射系统的原理,阐述了调频同步广播系统的组成,并且对该系统的实施情况进行了介绍.     

采用TEA5767的调频收音电路设计

介绍调频广播接收芯片TEA5767在便携式Video播放器中的应用,着重讲述了有关的FM接收、音频处理等方面的应用电路,并给出了在电路设计中应注意的问题。     

基于单片机和TEA5767HN的FM收音机系统的设计

为了在电子产品中嵌入立体声FM数字收音机功能。采用单片机AT89S52和TEA5767HN为硬件核心,运用I2C总线通信方式进行软件设计,给出了实现手动搜台、自动搜台等功能的FM数字调频收音机的设计方法。该方法采用PT2257对音频进行处理,以实现立体声输出,因而具有轻巧、方便、频带范围宽、低功耗、高灵敏度等特点,并可以嵌入MP3、手机、便携式播放器等小型电子产品中。     

基于I2C总线的嵌入式收音机模块设计

主要介绍了在个人数字助理(PDA)系统开发平台中，利用PHILIPS公司的FM收音机单芯片TEA5768HL通过I^2C总线进行通信来设计和实现数字调频立体声收音机模块。重点讲述了TEA5768HL的工作原理、收音机模块设计方案。此收音机模块具有高性能、低功耗、低成本、占PCB面积小、CPU控制方便等优点，同时它也适合应用于智能手机、MP3播放器等掌上嵌入式系统产品中。     

Analysis of the carrier-induced FM response of DFB lasers:theoretical and experimental case studies

A comprehensive analysis of the carrier-induced FM response of DFB lasers is given. Experimentally it is found that the FM response can sometimes vary strongly from chip to chip. In a number of cases anomalies either as a function of frequency or as a function of bias are observed. Theoretically, a dynamic model which includes spectral as well as longitudinal spatial hole burning is presented. The main feature of the model is that local variations of the Bragg wavelength caused by hole burning are rigorously and self-consistently taken into account. By comparing the experimental results with theoretical calculations, it is shown that in DFB lasers, spatial hole burning is an important phenomenon. The model confirms that the dynamic (FM) behavior can vary from DFB chip to DFB chip. The model shows that spatial hole burning is indeed the dominant factor which induces the anomalies that are found experimentally in the FM response     

A 1.2 mW RDS receiver for portable applications

A 0.9 V 1.2 mA fully integrated radio data system (RDS) receiver for the 88-108 MHz FM broadcasting band is presented. Requiring only a few external components (matching network, VCO inductors, loop filter components), the receiver, which has been integrated in a standard digital 0.18 /spl mu/m CMOS technology, achieves a noise figure of 5 dB and a sensitivity of -86dBm. The circuit can be configured and the RDS data retrieved via an I/sup 2/C interface so that it can very simply be used as a peripheral in any portable application. A 250 kHz low-IF architecture has been devised to minimize the power dissipation of the baseband filters and FM demodulator. The frequency synthesizer consumes 250 /spl mu/A, the RF front-end 450 /spl mu/A while providing 40 dB of gain, the baseband filter and limiters 100 /spl mu/A, and the FM and BPSK analog demodulators 300 /spl mu/A. The chip area is 3.6 mm/sup 2/.     

逐次逼近型模数转换器中的失配校准技术

设计了一种用于逐次逼近型模数转换器中的比较器失调和电容失配自校准电路.通过增加校准周期,该电容自校准结构即可与原电路并行工作,实现高精度与低功耗.校准精度可达14bit.采用该电路设计了一个用于逐次逼近型结构的10bit 3Msps模数转换器单元,该芯片在SMIC 0.18μm 1.8V工艺上实现,总的芯片面积为0.25mm2.芯片实测,在采样频率为1.8MHz,输入320kHz正弦波时,信号噪声失真比为55.9068dB,无杂散动态范围为64.5767dB,总谐波失真为-74.8889dB,功耗为3.1mW.     

On the thermal FM response of a semiconductor laser diode

The letter proposes a simplified transfer function for the thermal FM response of a semiconductor laser diode, derived from an approximate thermal model of the laser chip. Based on this, the dip in the overall FM response is analyzed theoretically. Experimental data on the FM response of DFB laser diodes are in excellent agreement with the proposed theory     

模拟锁相环NE564在FM解调电路中的应用

介绍了锁相鉴频电路的工作原理和模拟锁相环芯片NE564的结构与特点,并用该芯片设计了一款41.4MHz的FM解调电路,具有较强的实用性。     

The Test Engineer's Assistant: a design environment for testableand diagnosable systems

The Test Engineer's Assistant (TEA) is a set of computer-aided design (CAD) tools that helps the system design engineer meet testability requirements by construction. TEA addresses system design for testability at all levels of the design hierarchy, the lowest level being the board level. The design is represented as a graph where each node indicates a hardware component (or chip on a board) and each arc represents intercomponent connections. Attributes associated with the graph nodes and a set of rules and testing techniques that are incorporated in the tool databases are used to determine the design features that have to be incorporated into the design to meet test and diagnostic requirements. The tool operates on a design using a combination of algorithmic and heuristic techniques. The authors present the design methodology supported by TEA, discuss the techniques used by the TEA tools to obtain solutions for different design for testability requirements, and present an example of the use of TEA with a real system     

地面数字声音广播（DAB）及其覆盖规划的考虑

简要描述了近几年来研究开发的为移动、便携和固定接收服务的地面发射数字声音广播(DAB)系统总的特点、应达到的技术和运行要求。重点介绍了系统采用的最适合克服移动接收中出现的多径效应影响的先进源编码技术(MUSICAM)、信道编码技术(COFDM)等的基本原理、系统参数、并介绍了规划DAB业务时,在VHF/FM频段考虑的最佳频段及频谱利用改善情况,还提供了DAB单频网洛(SFN)覆盖的大体情况。其内容取材均来自1990～1992年EBU、CCIR等的最新文稿资料。