发射电台质量保证系统典型故障分析

本文根据作者多年维护发射电台质量保证系统的经验,对质量保证系统运行中常见故障的原因及处理方法进行了分析。     

熊本十年——我和韦晴光在日本（十三）

球队刚刚到达东京。12月l9日下午，电台首先广播：九州最大的超级市场寿屋倒产，负债2900亿日元。     

等待下一个四年

在我看来,国内的体育爱好者,大抵分为两类。一类身体力行,一类只看不练。后一类的更准确定义,应该是“竞技比赛视听爱好者”,他们以观看电视实况转播,收听电台广播和阅读纸媒比赛报道,为业余生活最大     

数字音频无线传输系统研制

数字音频无线传输系统是传输声音信号的音响器材,由发射机和接收机两大部分组成。发射机将声音信号转换为数字信号,通过无线电波发射出去。接收天线将收到的无线数字信号转换为音频信号送到外设备,完成音频信号的无线传输。现行的无线音频传输系统要么功能强大全面,但是价格高昂。要么功能简单,效果恶劣,无法使用。对于教学系统来说,前者资源浪费,后者不堪使用。本项目的目的就是针对课堂教学开发出一个低成本、高质量,切合实际的无线音频传输系统。略加改良,本体统可以在家庭影：,卡拉OK,校园广播等等领域应用,市场前景广大。     

风景戳上的广播电视塔

中央广播电视塔中央广播电视塔,坐落于北京西三环中路,塔高405米,东临秀美的玉渊潭,为中国第三、世界第五高塔,集广播电视发射和游览观光为一体。广阔的栈桥广场,汉白玉的退台环廊,宫灯型的塔楼,祈年殿式的塔座,让人流连忘返。站在238米高的露天平台和富丽堂皇的观景厅,可环视京城风貌。     

Tsw2500短波发射机功率模块故障及解析

随着TSW2500发射机在短波广播中使用,维护和处理故障在不断的探索.本文从该发射机的TSM功率模块的维护中,讲述几种常见的故障及处理方法.     

现代城市的新景观——电视塔

电视是群众日常休闲娱乐和接受信息的重要媒体。电视广播事业受到各国公私部门的重视。 电视台把电视信号和伴音信号分别调制在高频载波上,进行功率放大,再送到发射天线,以电磁波的形式辐射出去,被家用电视机     

视音频切换器信号的技术保障措施

0概述 我台是贵州省广播电视局直属高山骨干发射台,同时也是一个集广播、电视、微波于一体的综合类高山骨干发射台,肩负着为全省各大功率发射台无线传输中央一套广播节目(调频10KW)、贵州一套广播节目(调频10KW)、贵州一套电视节目(10KW)和中央一套电视节目(20KW),并为贵阳市及周边地区无线覆盖广播和电视信号的发射播出任务.由于我台的发射频率多、功率大、覆盖面广以及影响大等特点,因而,对我台的安全播出工作带来极大的工作压力,面临着新的考验.     

基于DRM技术探讨短波调幅广播发射系统的数字化改造

在现代,调幅广播具有很大的优势,其覆盖的范围很大、接收需要的成本相对较低,在我国具有大量的听众,也是进行宣传与进行文化娱乐的重要工具。但是其也存在明显的缺点,传输的质量不高、发射的功率大等,在科学技术空前发展的当前面临着严峻的挑战。数字化是调幅广播发展的必然趋势,发达国家关于这一方面的研究和实践较多,并在探索过程中制定了统一的调幅广播标准,被称为DRM标准。其音质高、传送方便,且不需要对频率进行规划设计,只需要适当的改进与调整就能够继续使用,过渡非常便利。     

达·席尔瓦1983

鲍勃·迪伦在低低吟唱着:要独自走过多少路,才能成为一个真正的男人?白鸽要飞越多少海洋,才能在沙滩上安息?《随风而逝》的歌声是伦敦球迷通过电台为达·席尔瓦送上的祝福。自从在与伯明翰的比赛中严重受伤后,达·席尔瓦一时间成为整个伦敦甚至整个世界谈论的话     

Carbohydrate ingestion improves endurance performance during a 1h simulated cycling time trial

This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue.     

Science and medicine of rowing: A review

The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae.     

我国体育市场管理法规研究

采用调查法和比较法对全国体育市场立法和管理现状进行调查,对部分较早出台并有一定代表性的省市的体育市场管理法规的立法和管理情况进行了研究,提出了体育市场管理立法和管理的原则、基本程序、措施及其一般模式,为规范全国体育市场管理提供参考依据。     

重新认识体育的社会关联

体育与政治之间存在一个悖论，体育的发展与经济实力之间没有直线相关，体育与教育部分重叠，体育与宗教最为近缘，体育可借用科学手段，体育的艺术禀性日益明显，体育与养生反映着两种人生观。     

上海社区体育竞赛参与者的特点探析

本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。     

对全面把握游泳训练环节的探讨

从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。     

我国优秀游泳运动员出发技术辅助训练的研究

为改进我国优秀游泳运动员的出发技术,采用观测和实验方法,通过拍摄运动员陆上和水下出发技术录像以及出发计时,对出发技术进行运动生物力学诊断和分析。在此基础上,根据运动员自身特点和不同泳姿提出相应的入水启动方式,并研制出发训练辅助器材,对出发预备姿势、腾起角度以及飞行远度和入水角进行控制。实践证明:这是一种快捷、有效的出发技术辅助训练方法。     

运动性呼吸肌疲劳与耐力性项目的运动能力

影响和限制耐力性运动项目的成绩的生理因素是复杂的和多方面的,取决于训练的强度和运动成绩.大强度持续性运动可导致呼吸肌疲劳.运动性呼吸疲劳可能在决定运动耐量方面起到关键的作用：一方面通过直接影响运动肌力量的生成（外周疲劳）,另一方面,通过肢体用力自感不安反馈引起工作肌运动单位输出功率下降（中枢疲劳）.对呼吸肌进行训练,可能有助于提高耐力性项目的运动成绩.     

Identifying home advantage in international tennis and golf tournaments

A regression analysis of competitors' tournament results in relation to their world rankings was proposed to identify the effect of home advantage in international ‘grand-slam’ tennis and ‘major’ golf tournaments. The results provided little evidence of home advantage in either the grand-slam tennis or the golf tournaments held in 1993. The only possible evidence of home advantage was found in the Wimbledon tennis and the US Open golf championships. Even these findings can be explained, at least partially, by (1) the availability of information concerning the low world rankings of the British tennis players competing at Wimbledon, and (2) selective entry, allowing only the world's top-ranked foreign golfers into the US open golf tournament. In both cases, the lower ranking home competitors have a greater opportunity to perform above their anticipated world rankings. Therefore, provided entry into tennis and golf tournaments is truly ‘open’ to both the host nation's representatives and foreign competitors alike, home advantage does not appear to be a major factor influencing the competitors' performance in such competitions. These findings may be explained by the relatively objective nature of the scoring systems used in tennis and golf, unlike the subjective influence of refereeing decisions on the results of team-games such as soccer.     

对欧洲足球技战术发展趋势的思考

结合欧洲足球技战术的发展特点,就鲁能泰山足球队的体能训练、技术训练、防守阵型、进攻方式、定位球、职业态度、球星培养等诸方面所存在的不足进行了分析,提出相应的改进意见。