GaAs Monolithic MIC's for Direct Broadcast Satellite Receivers

A 12-GHz low-noise amplifier (LNA), a 1-GHz IF amplifier (IFA), and an 11-GHz dielectric resonator oscillator (DRO) have been developed for DBS home receiver applications by using GaAs monolithic microwave integrated circuit (MMIC) technology. Each MMIC chip contains FET's as active elements and self-biasing source resistors and bypass capacitors for a single power supply operation. It also contairns dc-block and RF-bypass capacitors. The three-stage LNA exhibits a 3.4-dB noise figure and a 19.5-dB gain over 11.7-12.2 GHz. The negative-feedback-type three-stage IFA shows a 3.9-dB noise figure and a 23-dB gain over 0.5-1.5 GHz. The DRO gives 10.mW output power at 10.67 GHz, with a frequency stability of 1.5 MHz over a temperature range from -40-80°C. A direct broadcast satellite (DBS) receiver incorporating these MMIC's exhibits an overafl noise figure of /spl les/ 4.0 dB for frequencies from 11.7-12.2 GHz.     

12千兆赫卫星直播电视接收站

已研制了一种简单、低成本的12千兆赫卫星直播电视接收站.给出了该站与主要微波部件如混频器、参放等的性能.该站在南京长期试收了日本直播卫星播出的节日,达到了预期的良好效果.     

卫星传输到卫星直播

1 前言 19世纪中叶以前,人造地球卫星还是一种科学幻想,只是出现在民间传说和神话故事之中。到1945年10月,才有人提出了向地球赤道上空35786公里的静止卫星轨道上发射卫星,利用这样的卫星作为无线电转播站进行地面远距离通信和广播的设想,而如     

广播卫星电视接收机对SMAP卫星L波段微波辐射计的射频干扰特征分析

该文通过融合SMAP卫星L波段交叉极化亮温,建立基于密度和强度空间分布特征的多重迭代聚类射频干扰(RFI)检测识别算法.分析并提取日本典型RFI源(广播卫星电视接收机)密度和累积强度的时空分布和变化特征.电视接收机作为典型的RFI源,主要分布在日本城市化水平和范围均相对较大的区域(条状或面状),局部区域内分布点圆状RF...     

广播卫星电视接收机对SMAP卫星L波段微波辐射计的射频干扰特征分析

该文通过融合SMAP卫星L波段交叉极化亮温,建立基于密度和强度空间分布特征的多重迭代聚类射频干扰(RFI)检测识别算法.分析并提取日本典型RFI源(广播卫星电视接收机)密度和累积强度的时空分布和变化特征.电视接收机作为典型的RFI源,主要分布在日本城市化水平和范围均相对较大的区域(条状或面状),局部区域内分布点圆状RFI(可能为微波辐射基站),导致局地化RFI累积强度具有很高的水平.同时,在日本其他区域也检测到独立分布的点圆状RFI,干扰强度和范围相对局限.2018年开始,日本RFI整体分布范围和强度能级呈下降趋势.典型RFI源特征分析对于我国建立RFI检测、识别及抑制模型具有重要意义.     

直播卫星技术在我国应用的前景

由于直播卫星的最大优势是只用有限的1~2颗卫星,就可以向无限数量的家庭户直播上百套电视节目。根据我国的国情,从技术层面、政策层面和管理层面,全方位地阐述了在我国发展直播卫星技术和前景。指出了卫星电视直播到家庭将成为21世纪的世界潮流。直播卫星发射后将给现有的有线数字电视带来很大的冲击,所以政府主管机构将直播卫星定位为“对有线数字电视的补充的延伸”。两者的关系是“优势互补、各展其长、相对分工、互为补充、互为备份、适当竞争、共同发展”。     

《彩色电视广播接收机基本技术参数》标准介绍

1 前言随着彩色电视技术的迅速发展和逐步成熟,尤其是数字技术开始应用到模拟机中,彩色电视机的功能由过去的单一制式、单一功能变成多制式、多功能、多用途的电视显示终端。并且在此期间,制定了GB/T17309.1-1998和SJ/T11157-1998新的电和声的测量方法。原GB/T10239-1994中的彩色电视广播接收机的电、光、声、色性能已不能适应目前彩色电视机发展的需要,因此必须进行修改。根据信息产业部科技司和全国音频、视频及多媒体系统与设备标准化技术委员会的指示精神,将彩色电视广播接收机的电、光、声、色常温性能从GB/T10239-1994《彩色电视…     

Satellite Beam Optimization for the Broadcasting Satellite Service

In view of the forthcoming ITU Regional Administrative Radio Conference for the planning of the Broadcasting Satellite Service at 12 GHz for the American Continent to be held in 1983, there is a need for a means to transfer the service quality requirements for a Broadcasting Satellite Service into a consistent set of satellite and receiving terminal parameters.     

Efficient Non-Pilot-Aided Channel Length Estimation for Digital Broadcasting Receivers

Channel estimation and equalization techniques are crucial for the ubiquitous broadcasting systems. Conventional receivers for most broadcasting or wireless standards preset the channel length to the maximal expected duration of the channel impulse response for the adopted channel estimation and equalization algorithms. The excessive channel length often significantly increases the implementational complexity of the wireless receivers and leads to the redundant information which would induce the additional estimation errors. Moreover, such a scheme does not allow the dynamic memory allocation for variable channel lengths. This could further increase the power consumption and reduce the battery life of a mobile device. The knowledge of the actual channel length would, in principle, help the system designers decrease the complexity of the channel estimators using maximum likelihood (ML) and minimum-mean-square-error (MMSE) algorithms. In this paper, we address this important channel length estimation problem and propose a novel autocorrelation-based algorithm to estimate the channel length without the need of pilots or training sequence. The associated threshold for the channel length estimation depends on the sample size, the signal-to-noise ratio and the leading/last channel coefficients. In addition, we provide the mean-square analysis on the effectiveness of the proposed non-pilot-aided channel length estimator through Monte Carlo simulations.      

基于广播电视直播卫星的应急广播前端系统的建设思路

本文简要论述了基于广播电视直播卫星的应急广播前端系统建设思路,介绍了直播卫星应急广播系统的实现机制、指令接收、审核以及发布流程,具体包括应急广播系统结构、实现机制、直播卫星平台前端系统、应急广播接收审核系统、应急广播发布系统等.     

浅析我国直播卫星平台及其运营模式

中星9号直播卫星6月9日在西昌卫星发射中心发射升空后,作为广电人如何看待直播卫星的发展?从直播星的特点、直播星的技术、直播星发展的历史展开,重点分析我国直播星的政策背景、运营策略,以及将会给现有有线电视网络带来的影响与冲击。     

Advanced Conditional Access System for Digital Broadcasting Receivers Using Metadata

This paper presents an advanced conditional access system (CAS) for digital broadcasting receivers using program-related information called metadata. Digital broadcasting receivers using metadata (DBRM) provide services enhanced by using metadata and content stored in receivers, but it is so easy to edit stored content by using metadata that broadcasters require a content usage control mechanism for DBRM. The advanced CAS provides a secure environment for content and metadata in digital broadcasting receivers by preventing tampering and ensuring that only metadata certified by the broadcaster can be used. To evaluate the advanced CAS, we also developed a smart card and a prototype receiver on a PC. We have demonstrated in an implementation experiment that the advanced CAS can be implemented securely and utilized in broadcasting services using DBRM.     

An Assessment of the Potential Terrestrial Interference Due to Direct Broadcast Satellite Television Receivers

The potential interference of spurious, radiation from the local oscillators of direct broadcast satellite (DBS) television receivers to terrestrial 11 GHz microwave radio services is examined. Typical parameters for DBS receivers are identified and used in a computer simulation to calculate the aggregate effect of a large number of units distributed about a terrestrial repeater site. The results of the analysis show that for a local oscillator frequency of 11.2 GHz, DBS LO leakage of -70 dBW/unit, and a density of 2600/km²(1000/mi²) the cumulative interference power would be comparable to the thermal noise level of a terrestrial radio system under realistic conditions. Methods of scaling the results for other system parameters are also presented.     

我国广播电视卫星事业发展状况

我国的卫星广播电视事业正在不断发展,随着其影响的不断扩大,关心它的人也越来越多。另外,近一年来由于卫星转发器的供求关系,以及其它一些因素,广播电视所用的转发器发生了一些变化,给卫星信号的接收带来一些困难。本文旨在从卫星广播电视发展的历程、现状、趋势,以及“东方红”系列卫星的特点、新技术的应用等诸方面介绍大家所关心的情况,并提供所需的信息,以便有关部门安排工作时作参考。     

我国卫星广播事业的发展

本文回顾了我国卫星广播电视事业发展的历史，指出了卫星广播的地位和作用，在分析了目前卫星广播事业发展中存在的困难的同时，提出了今后的发展方向和措施。     

Channel Modeling for Multiple Satellite Broadcasting Systems

In this contribution we present the results of a study on land mobile satellite channel models for satellite systems with multiple satellites. The slow fading of our channel model for several satellites is based on a Markov channel state model for joint processes while the Probability Density Function (PDF) of the signal amplitude within each state is fitted to the Loo distribution. The correlation between two satellite channels and the channel spatial autocorrelation have also been studied. We show that a channel state model that uses a Markov state model of order one or of a fixed higher order is not appropriate if the state duration is of very high importance, which can be the case in the process of system planning. Therefore, we propose a dynamic higher order Markov state model for joint processes that depends on the current state duration. This approach models precisely any PDF of the channel state duration for both single and multiple satellite broadcasting systems while having a significantly lower computational complexity than a fixed higher order Markov model. It models the channel states of the whole system correctly, as well as the channel states of each satellite observed independently. It is able to capture the state correlation between multiple satellites. We also study possible approximations of the proposed models in order to reduce their computational complexity while having a good PDF match. Our channel state models are validated by measurements.      

广播电视卫星上行站的系统维护

本文从实际维护需要和可行性出发,着眼于系统维护,介绍了广播电视卫星上行站供电、节目源引接、中频、射频、高功放、天馈线等分系统及整个上行系统的技术维护,希望有益于广播电视卫星上行站科学维护工作的推进。     

Transmission System for the Television Broadcasting Satellite

Standardization of transmission system for television satellite broadcasting with multiple sound and/or data signals for an operational broadcasting satellite system is under study in Japan. Based upon result obtained from the BSE experiment, several transmission systems have been developed at the NHK (Japan Broadcasting Corporation).     

卫星数据广播应用技术

本文从卫星数据广播的技术特点和优势出发,介绍了卫星数据广播应用的体系结构和协议,讨论了多路广播等在卫星领域的应用前景,卫星数据广播关键技术问题与技术难点,并分析了目前国内卫星数据广播需要关注的问题。