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GB/T 26252-2010 VHF/UHF频段地面数字电视广播频率规划准则

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基本信息
标准名称:VHF/UHF频段地面数字电视广播频率规划准则
英文名称:Frequency planning criteria for digital terrestrial television broadcasting in the VHF/UHF bands
中标分类: 通信、广播 >> 广播、电视网 >> 节目传输
ICS分类: 电信、音频和视频技术 >> 音频、视频和视听工程
发布部门:中华人民共和国国家质量监督检验检疫总局 中国国家标准化管理委员会
发布日期:2011-01-14
实施日期:2011-06-01
首发日期:2011-01-14
作废日期:
主管部门:全国广播电影电视标准化技术委员会
提出单位:国家广播电影电视总局
归口单位:全国广播电影电视标准化技术委员会
起草单位:国家广播电影电视总局数字(高清晰度)电视标准工作组、数字电视地面传输国家标准特别工作组、广播电视规划院、北京北广电子集团有限责任公司、北京同方吉兆科技有限公司
起草人:章之俭、逯贵祯、冯景锋、高凤吉、高少君等
出版社:中国标准出版社
出版日期:2011-06-01
页数:28页
适用范围

本标准规定了GB 20600-2006的地面数字电视频率规划用参数及方法。
本标准适用于VHF/UHF频段的地面数字电视广播系统覆盖网规划。

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所属分类: 通信 广播 广播 电视网 节目传输 电信 音频和视频技术 音频 视频和视听工程
【英文标准名称】:Agriculturalandforestrymachines-Centrepivotandmovinglateraltypesirrigationmachines-Safety.
【原文标准名称】:农林业用机械.中心枢纽和侧向移动型灌溉机械设备.安全
【标准号】:NFU02-014-2009
【标准状态】:现行
【国别】:法国
【发布日期】:2009-08-01
【实施或试行日期】:2009-08-29
【发布单位】:法国标准化协会(FR-AFNOR)
【起草单位】:
【标准类型】:()
【标准水平】:()
【中文主题词】:
【英文主题词】:Agriculturalengineering;Agriculturalmachines;Agriculture;Definitions;Design;Electricalsafety;Energysupplysystems(buildings);Fieldirrigation;Forestry;Hazards;Holdingdevices;Hoses;Irrigation;Irrigationplants;Marking;Mechanicalsafety;Protectivemeasures;Reelmachinesystems;Safety;Safetyengineering;Safetyofmachinery;Safetyrequirements;Specification(approval);Stability;Startingdevices;Userinformation
【摘要】:
【中国标准分类号】:B91
【国际标准分类号】:65_060_35
【页数】:21P;A4
【正文语种】:其他


Product Code:SAE J406
Title:Methods of Determining Hardenability of Steels
Issuing Committee:Carbon And Alloy Steels Committee
Scope:This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden.Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels and subsize method for bars less than 32 mm (1-1/4 in) in diameter. Methods for determining case hardenability of carburized steels are given in SAE J1975.Any hardenability test made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing.For routine testing of the hardenability of successive heats of steel required to have hardenability within certain limits, it is sufficient to designate hardenability simply in terms of distance from the quenched end to the point at which a certain hardness is obtained. This designation may also be adequate for comparing steels of different compositions to see whether they have similar hardenability.Hardenability limits for specifying steel in this manner are obtained by measuring the hardenability of a steel which has proved satisfactory for the use intended. The hardenability test may be used in this way as an empirical test.For new components where manufacturing experience is lacking, hardenability data may be effectively used to estimate the hardness profile provided by any given steel. Attendantly, the ability to predict hardenability from chemical composition has become increasingly important when comparing various steel grades or developing new steels for specific applications. One such procedure is described in Appendix A. Other hardenability prediction methods are available from the selected references in Section 2. However, it should be emphasized that the use of any hardenability prediction procedure does not preclude the importance of conducting Jominy end-quench tests to determine the actual hardenability of any specific grade of steel.Hardenability data may be used to estimate hardnesses obtainable with any steel in new machine parts not yet in production and not similar to any parts on which production experience is available. Various hardenability application methods are described in the selected references, Section 2.1, 23 to 25. It appears none of these methods are precise, but these are often useful for estimation purposes. Final correlation on actual parts is necessary.