标准化场地衰减的测量.doc

Compliance Certification Services (Shenzhen) Inc.文件编号: PA-007标准化场地衰减的量测1.0 目的此作业流程书乃制定*公司每一年校正其开放式测试场地之标准化场地衰减之标准作业流程。2.0 适用范围*公司之开放式测试场地及外部单位委托*公司校正之开放式测试场地。3.0 参考文件ANSI C63.4: 1992VCCI V-3/01.04, APPENDIX ICISPR 16 & 16-14.0 定义场地衰减: 为一对称性、平衡性、无衰减可调式发射偶极天线之输入能量与一类似对称性、平衡性、无衰减可调式接收偶极天线之输出能量在一平坦之反射平面及特定之天线极性、区隔及高度之比率。 它是测量二个天线在传输过程之衰减。标准场地衰减: 由发射及接收天线之天线因素分开之场地衰减(全部为线性单位)。水平极性: 天线设定在水平方位。垂直极性: 天线设定在垂直方位。VDIRECT: 见步骤5VSITE: 见步骤4AFTOT (=Correction factor): 见Table 6 for ANSI，Table 7 for VCCIAFTX: 偶极发射天线之因素AFRX: 偶极街接收天线之因素AN: (NSA) Theoretical: 见Table 1-2 for ANSI，Table 4-5 for VCCIDeviation: 即场地衰值5.0 责任技术部: 负责量测之执行品管部: 监督量测之确实性，保管量测记录6.0 程序标准化场地衰减的测量需考虑水平与垂直极化两种。根据下列步骤测量ANSI C 63.4 Table1与Table2的频率点，CISPR 22 Table3的频率点与VCCI标准Table4与Table5的频率点标准化场地衰减。步骤1.使用可调整长度的偶极天线作为发射与接收天线。针对每个测量频率调整它们的长度至半波长。步骤2.参考Table1到Table5，固定发射天线于一特定高度h1且位于在作噪声测量时待测物的中心点。连接同轴电缆从信号产生器至发射天线。设定信号产生器发射频率至测量频率且输出电压至一信号噪声比（S/N ratio）足够的读值。步骤3.使用测量噪声用的天线当作接收天线，并将其架于距离发射天线3公尺或10公尺距离的天线架上。连接同轴电缆从测量接收仪或频谱分析仪至接收天线。步骤4.调整测量接收仪如同在作噪声测量一样至测量频率且接收天线参考Table1至Table5在特定高度 h2 范围内升降。测量并记录接收到的最大电压值 VSITEdBV。当作垂直极化测量时，注意保持天线底部尖端离地面至少25公分。步骤5.将两条同轴电缆从发射与接收天线端拔出，并利用电缆连接器接在一起。信号产生器输出电压保持与步骤2相同读值并调整测量接收仪至测量频率，量测并记录接收到的读值 VDIRECTdBV。步骤6.使用下列方程式推导出标准化场地衰减NSA (VDIRECT)(VSITE)AFTX AFRX AFTOT(NSA) (dB)其中AFTX：发射天线的天线因素 (参考偶极发射天线的天线因素)AFRX：接收天线的天线因素 (参考偶极接收天线的天线因素).注意：如果测量频率点并未列于偶极天线的天线因素表，使用内插法计算天线因素。NSA：由于天线间与地面相互阻抗效应所需的修正因素。参考Table6的ANSI C 63.4与Table7的VCCI标准的修正值。注意：Table6与Table7未列出的测量距离或频率，修正因素值视为零。步骤7.根据标准化场地衰减工作表内的指引与上述步骤所量得之读值计算标准化场地衰减和与理论上的标准化场地衰减的偏差。注意：查阅Table1至Table5取得理论上的标准化场地衰减值。步骤8.重复步骤2至步骤7完成Table1至Table5在其它频率时的标准化场地衰减。02.0803 PA-007(标准化场地衰减的测量) Page 10 of 10 Table 1.ANSI C63.4 Theoretical Normalized Site Attenuation for Ideal Site(Recommended Geometry for Tunable Dipoles, Horizontal Polarization)PolarizationHorizontalHorizontalR Metersh1 Metersh2 MetersfM3*21-4AN (dB)1021-4AN (dB)3011.024.1358.821.6407.019.4455.517.5504.215.9602.213.1700.610.980-0.79.290-1.87.8100-2.86.7120-4.45.0125-4.74.6140-5.83.5150-6.32.9160-6.72.3175-6.91.5180-7.21.2200-8.40.3250-10.6-1.7300-12.3-3.3400-14.9-5.8500-16.7-7.6600-18.3-9.3700-19.7-10.6800-20.8-11.8900-21.8-12.91000-22.7-13.8Table 2.ANSI C63.4 Theoretical Normalized Size Attenuation for Ideal Site(Recommended Geometry for Tunable Dipoles, Vertical Polarization)fMMHzR=3mh1=2.75mR=10mh1=2.75mh2 (m)AN (dB)h2 (m)AN (dB)302.75412.42.75418.8352.39411.32.39417.4402.13410.42.13416.2451.9249.51.92415.1501.7548.41.75414.2601.5046.31.50412.6701.3244.41.32411.3801.1942.81.19410.2901.0841.51.0849.2100140.6148.412014-0.7147.512514-0.9147.314014-1.5145.515014-2.0144.716014-3.1143.917514-4.1143.018014-4.5142.720014-5.4141.625014-7.014-0.630014-8.914-2.340014-11.414-4.950014-13.414-6.960014-14.914-8.470014-16.314-9.780014-17.414-10.990014-18.514-12.0100014-19.414-13.0Table 3.CISPR 22 Theoretical Normalized Size Attenuation for Ideal Site(Recommended Geometry for Tunable Dipoles)PolarizationHorizontalVerticalR (m)331010331010h1 (m)121211.511.5h2 (m)1 to 41 to 41 to 41 to 41 to 41 to 41 to 41 to 4f (MHz)AN (dB)3015.811.029.824.18.29.316.716.93513.48.827.121.66.98.015.415.64011.37.024.919.45.87.014.214.4459.45.522.917.54.96.113.213.4507.84.221.115.94.05.412.312.5605.02.218.013.12.64.110.711.0702.80.615.510.91.53.29.49.7800.9-0.713.39.20.62.68.38.690-0.7-1.811.47.8-0.12.17.37.6100-2.0-2.89.76.7-0.71.96.46.8120-4.2-4.47.05.0-1.51.34.95.4125-4.7-4.76.44.6-1.60.54.65.1140-6.0-5.84.83.5-1.8-1.53.74.3150-6.7-6.33.92.9-1.8-2.63.13.8160-7.4-6.73.12.3-1.7-3.72.63.4175-8.3-6.92.01.5-1.4-4.92.02.9180-8.6-7.21.71.2-1.3-5.31.82.7200-9.6-8.40.60.3-3.6-6.71.02.1250-11.7-10.6-1.6-1.7-7.7-9.1-0.50.3300-12.8-12.3-3.3-3.3-10.5-10.9-1.5-1.9400-14.8-14.9-5.9-5.8-14.0-12.6-4.1-5.0500-17.3-16.7-7.9-7.6-16.4-15.1-6.7-7.2600-19.1-18.3-9.5-9.3-16.3-16.9-8.7-9.0700-20.6-19.7-10.8-10.6-18.4-18.4-10.2-10.4800-21.3-20.8-12.0-11.8-20.0-19.3-11.5-11.6900-22.5-21.8-12.8-12.9-21.3-20.4-12.6-12.71000-23.5-22.7-13.8-13.8-22.4-21.4-13.6-13.6Table 4.VCCI Theoretical Normalized Size Attenuation for Ideal Site(Recommended Geometry for Tunable Dipoles, Horizontal Polarization)PolarizationHorizontal polarizationMeasurement distance3 m10 mTransmitting height h12 m2 mReceiving height h214 m14 mFrequency MHzNSA AN (dB)303540455011.08.87.05.54.224.121.619.417.515.9607080901002.20.6-0.7-1.8-2.813.110.99.27.86.7120140160180200-4.4-5.8-6.7-7.2-8.45.03.52.31.20.3250300400500-10.6-12.3-14.9-16.7-1.7-3.3-5.8-7.66007008009001000-18.3-19.7-20.8-21.8-22.7-9.3-10.6-11.8-12.9-13.8Table 5.VCCI Theoretical Normalized Size Attenuation for Ideal Site(Recommended Geometry for Tunable Dipoles, Vertical Polarization)PolarizationVertical polarizationMeasurement distance3 m10 mTransmitting height h12.75 m2.75 mFrequency MHzReceivingheightNSAReceivingheightNSAh2 (m)AN (dB)h2 (m)AN (dB)30354045502.7542.3942.1341.9241.75412.411.310.49.58.42.7542.3942.1341.9241.75418.817.416.215.114APP2607080901001.5041.3241.1941.084146.34.42.81.50.61.5041.3241.1941.0841412.611.310.29.28.41201401601802001414141414-0.7-1.5-3.1-4.5-5.414141414147.55.53.92.71.625030040050014141414-7.0-8.9-11.4-13.414141414-0.6-2.3-4.9-6.960070080090010001414141414-14.9-16.3-17.4-18.5-19.41414141414-8.4-9.7-10.9-12.0-13.0Table 6.ANSI C63.4 Correction Factor (AFTOT )Antenna to be used: Tunable dipoleAntenna factor calibration condition: Free spaceHorizontal PolarityR = 3 mh1 = 2 mh2 = 1 to 4 m scanVertical PolarityR = 3 mh1 = 2.75 mh2 = (see table 2)fMMHzAFTOT303.12.9354.02.6404.12.1453.31.6502.81.5601.02.070-0.41.580-1.00.990-1.00.7100-1.20.1120-0.4-0.2125-0.2-0.2140-0.10.2150-0.90.4160-1.50.5175-1.8-0.2180-1.0-0.4Table 7.VCCI Correction Factor (NSA)Antenna to be used: Tunable DipoleAntenna factor calibr