数字调频广播发射机测试方法

本文对数字调频广播发射机的结构及测量条件进行了介绍，针对其技术特点，对相位噪声、频谱模板、带肩、邻频道带内无用发射功率及邻频道带外无用发射功率等重要指标的测试方法进行了详细说明。

数字电视发射机技术及应用

随着信息化时代的到来,我国的广播电视也逐渐步入数字化时代。数字电视发射技术依靠其优势迅速取代了传统的电视发射技术。本文主要分析探讨数字发射技术的特点及应用。

卫星导航系统与射电天文兼容性分析

基于国际电联对射电天文业务的特殊保护要求，介绍了《无线电规则》决议739射电天文业务（1610～1618 MHz）邻近频段内的RNSS业务（1559～1610 MHz）带外发射的门限要求。采用ITU-R M？1583建议书对非GSO系统在射电天文站址处产生的无用发射电平的分析方法进行评估。通过仿真计算，提出北斗卫星导航系统MEO、 IGSO和GEO卫星带外抑制限值，在确保北斗卫星导航系统自身系统稳定运行的条件下，满足对射电天文业务的特殊保护要求。

Compensation Method： New Perspectives

The compensation method aiming to reduce the irradiation on the user＇s body and to form a weak field area （a dark spot） in an antenna near region is considered. The results of the method development for the use in a narrow frequencies range are given. They show that under realistic conditions the compensation method allows reducing the irradiation power by a factor of 3-4 and more. The pattern changes are predictable and small, if the points of antennas placement are selected correctly. The dark spot necessity near the transmitter is not limited by mobile communication. A man often uses a low-power radio station, which is placed nearby in a vehicle, and it is necessary to protect from irradiation not only user but also other passengers. In the paper, it is shown that broadband field compensation can be achieved in various structures where the needed anti-phase fields are created either by identical antennas or by radiators located at equal distance from the compensation point, or by flat reflectors.

欧盟无线产品新版标准开始强制执行

自2015年1月1日起,欧盟将对进入欧盟市场的带有2.4GHz及5GHz频段的宽带接口设备实施强制新ETSI测试标准──EN 300 328 V1.8.1及EN 301 893 V1.7.1。所有依据旧版标准出具的EC符合性声明已不再有效,不符合新标准的产品将不得在欧盟市场销售。EN301 893标准适用范围为无线局域网使用,并在5150~5350 MHz和5470~5725 MHz频段下运行的5GHz的WLAN设备。