1、 STD-EIA TSB72-ENGL 2778 m 3234hUO Ob14223 874 m TIAIEIA TELECOMMUNICATIONS SYSTEMS BULLETIN Report on EME Evaluation for RF Cabinet Emissions Under FCC IMPE Guidelines _ TSB92 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Eiectronlc Industries Alliance Copyright Telecommunications Industry Association Pr
2、ovided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE TIA/EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitat
3、ing interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of TIA/EIA from manufacturi
4、ng or selling products not conforming to such Standards and Publications, nor shaU the existence of such Standards and Publications preclude their voluntary use by those other than WEIA members, whether the standardis to be used either domestically or internationally. Standards, Publications and Bul
5、etins are adopted by EIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, WETA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Publication, or Bulletin. Technical Bulleti
6、ns are distinguished from TiA/ELA Standards or Interim Standards, in that they contain a compilation of engineering data or information useful to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not inte
7、nded to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in f
8、uture revisions of this Bulletin are encouraged to do so. It is the intention of the fomulating committee to revise and update this Bulletin from time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (From Project
9、No. 4222, formulated under the cognizance of the TIA R-8.17 Subcommittee on Radiation Exposure). Published by OTELECOMMNICAONS INDUSTRY ASSOCIATION 1998 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to the current Catalog of EIA, JEDEC and TIA STAN
10、DARDS and ENGI“G PUBLICATIONS or caii Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-397-7956) All rights reserved Printed in U.S.A. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking p
11、ermitted without license from IHS-,-,-STD*EIA TSB92-ENGL 1778 3234b00 Ob14225 b1i7 = TSB92 TABLE OF CONTENTS 1 . 2 . 3 . 3.1 3.2 3.3 3.4 4 . 4.1 4.2 5 . INTRODUCTION . i FCC EME LIMITS i LIMIT CASE ANALYSIS . 3 CALCULATION OF EME LEVEL BASED ON THE FCC LIMIT OF -13 DBM FOR THE SUM OF THE TRANSMITTER
12、 HARMONICS (1-10) 3 EXAMPLE SPREADSHEET CALCULATIONS 3 CALCULATIONS AT REPRESENTATIVE FREQUENCIES: 3 MHZ . 2 GHZ . 4 TABLE1 . 4 MEASUREMENT METHOD . 4 TRANSMITTER SITE CONSIDERATIONS 5 MANUFACTURER INSTALLATION RECOMMENDATIONS 5 SITE COMPLIANCE 6 SUMMARY 6 APPENDIX A . Al APPENDIX B . BI I Copyright
13、 Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-EIA TSB72-ENGL 1998 3234b0 ObLq22b 583 TSB92 I. Introduction The purpose of this report is to develop and document methods and procedu
14、res of evaluation to establish cabinet emission levels with respect to the FCC defined EME (electromagnetic exposure) limits. Specifically the EME characterization is of box level equipment only, e.g., a fixed station, vehicular, or similar equipment, and is not a substitute for a complete transmitt
15、er site EA (Environmental Assessment) by means of computation or site measurement. A limit case analysis based on the FCC part 90 type acceptance spurious emissions regulation limits will be conducted herein to show that type accepted equipment at the box level is within the FCC MPE (maximum permiss
16、ible exposure) limits. 2. FCC EME Limits Controlled and general population limits as defined in 47 CFR 1 .I 31 O. Table I. Table i. MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMITS (A) Limits for OccupationallControlled Exposure Frequency Electric Field Magnetic Field Power Density Averaging Time Range Str
17、ength (E) Strength (H) (SI EI, IHI2 or S (MHz) (VIm) (Alm) (mW/sq. cm) (minutes) 0.3-3.0 614 1.63 (1 OO)* 6 3.0-30 1842lf 4.89if (9OOIf)* 6 30-300 61.4 0.163 I .o 6 300-1 500 - - f/300 6 - 5 6 1500-1 00,000 - 1 Copyright Telecommunications Industry Association Provided by IHS under license with EIAN
18、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,- STD-EIA TSB72-ENGL 1998 m 3234b00 Ob14227 41T m TSB92 (B) Limits for General PopulationlUncontrolled Exposure Frequency Electric Field Magnetic Field Power Density Averaging Time Range Strength (E) Strength (H) (SI El
19、2, HI2 or S (MHz) (Vim) (Alm) (mWIsq. cm) (minutes) 0.3-1.34 614 1.63 (1 OO)* 30 1.34-30 824lf 2.19lf (1 80/f)* 30 30-300 27.5 0.073 0.2 30 300-1 500 _ fll500 30 1500-1 00,000 - - 1 .o 30 f = frequency in MHz *Plane-wave equivalent power density 2 Copyright Telecommunications Industry Association Pr
20、ovided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TSB92 3. Limit Case Analysis This analysis is structured to show that equipment that conforms to FCC emission limits for the carrier and its harmonics, through the tenth, will resul
21、t in an equipment level EME that is compliant to the MPE limits as set forth in 47 CFR 1.1310. 3.1 Calculation of EME level based on the FCC limit of -13 dBm for the transmitter harmonics (140). The limit case calculation will compute the resultant EME level, as a percent of the MPE level, of a tran
22、smitter that exhibits the maximum allowable cabinet emission limits as defined in 47 CFR 90.210. This maximum level is a spurious emission that is attenuated by at least 43 + 10 log(P) dB, or equivalently -13 dBm. The cabinet emissions will be considered to be emitted from a point source. As such it
23、 is necessary to define a distance at which the power density will be calculated. For practical purposes, and because ANSVIEEE C95.3-I 991 specifies it for measurement separation, a minimum working distance of 20 cm will be specified. This will allow controlled population to be sufficiently close to
24、 the equipment to allow direct observation or normal service interface through a terminal device or similar equipment. 3.2 Example spreadsheet calculations Calculation method: 1. Compute the power density for each harmonic at the maximum allowed FCC radiated level (-13 dBm), at the specified distanc
25、e, 20 cm, for the horizontal polarization, “where Prad is the power radiated”. Power Density = S = (Prad x 1.64)/(II x rZ) mW/cm2, 20 cm 2. Compute percent of MPE for each harmonic. %MPE(fn) = 100 x S(fn)/MPE(fn) 3. %MPE(horizontal polarization) = Sum of %MPE(fn), n = 1-10. 4. Repeat steps 1-3 for v
26、ertical polarization. 5. Total %MPE = %MPE(horizontal) + %MPE(vertical) 3 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-EIA TSB72-ENGL 1998 323Lib00 DbLLi227 272 TSB92 3.3
27、 Calculations at representative frequencies: 3 MHz - 2 GHz. Table1 Resultant Controlled and General Population Percentage of MPE for Maximum FCC Cabinet Radiation Levels. =undamental Frequency (MHz) 3 30 450 900 I900 Controlled % MPE I .26E-02 3.27E-02 8.58E-03 6.98 E-O3 6.54E-03 Genera I % MPE 6.30
28、E-02 1.64E-01 4.2 9E-02 3.49E-02 3.27E-02 Spreadsheets showing the complete set of calculations (horizontal and vertical polarization) for each frequency and its harmonics are included in appendix A. The highest level computed, as shown in Table 1 above at a fundamental of 30 MHz, is more than 600 t
29、imes 1/(1.64E-01/100)=609.8 below the FCC MPE limits. But, one must consider what would happen if there were some additional spurious energy that was not at the harmonic frequencies. To reach the MPE limits at this fundamental frequency would require a total of about 6000 individual spurs each radia
30、ting at exactly the FCC spurious limit with equal horizontal and vertical polarized energy. This is just unheard of, and no performance even remotely close to this number of spurs at this magnitude has been observed. Therefore, this level of margin is considered acceptable. 3.4 Measurement method Th
31、e measurement method is as stated in EIA/TIA 603 section 2.2.12 Radiated Spurious Emissions with the following modification: The carrier-radiated emission, terminated in a non-radiating load, must also be measured for horizontal and vertical polarization. 4 Copyright Telecommunications Industry Asso
32、ciation Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-EIA TSB72-ENGL 3778 m 3234b00 Ob34230 TO4 m TSB92 4. Transmitter Site Considerations 4.1 Manufacturer installation recommendations Proper installation of the transmitt
33、er, and more importantly its antenna, is necessary for the equipment to meet the FCC MPE requirements. Some form of the following in the installation manual is required to assure that the manufacturers meet their requirements to so inform the user. IMPORTANT ELECTROMAGNETIC EMISSION INFORMATION In A
34、ugust, 1996, the Federal Communications Commission (FCC) adopted an updated safety standard for human exposure to radio frequency (RF) electromagnetic energy emitted by FCC regulated equipment. The manufacturer of this equipment subscribes to this same updated safety standard for the use of its prod
35、ucts. Vehicular Station Operation With a properly installed vehicular antenna, the following procedures will assure that RF energy exposure of bystanders external to a vehicle is lower than the limits adopted by the FCC. With a radio that has less than 50 watts of output power, transmit only when by
36、standers are at least two feet away from the antenna. With 50 Watts or more, transmit only when they are separated three feet or more. Control Station Operation The following will assure that bystanders and operators of control stations are exposed to RF energy levels lower than the limits adopted b
37、y the FCC. Performance is best when the antenna is located on the rooftop of the building in which the station is located. In all cases, however, the antenna should be installed so that operators and bystanders are at least two feet away from it when a transmitter with less than 50 Watts of output p
38、ower is operated. If the transmitter has 50 Watts output or more, the operators and bystanders should be three feet or more away from it. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from
39、 IHS-,-,-STD-EIA TSB72-ENGL 1798 3234b00 Ob14231 7LiO TSB92 Base Station Operation This Company certifies that it has determined that the equipment covered by this manual complies with the guidelines for evaluating the environmental effects of radiofrequency (RF) radiation from FCC regulated transmi
40、tters as described in ET Docket No. 93-62 Report and Order adopted August I, 1996 and subsequent rulings. This certification is based upon the installation being made in accordance with the instructions supplied with the equipment and in recognition that because of the characteristics of a particula
41、r site; a determination of compliance with respect to any particular site can be made only upon an analysis of the installation. This paragraph should be followed by a description of the standard and a typical installation. An example is given in Appendix B. 4.2 Site compliance This analysis is for
42、box level elements, which are part of a transmitter site, but do not constitute a complete site. Conformance of the box level equipment to the FCC emission limits implies the box is within recommended MPE level limits, but does not imply that the transmitter site conforms with FCC MPE guidelines. Ad
43、ditional computations or measurements at each site will determine what precautions are necessary for each particular site to meet MPE guidelines. Proper installation of antenna distribution systems, work practices, etc. are required for a site to conform with FCC guidelines for human exposure to ele
44、ctromagnetic energy. 5. Summary Equipment that conforms to FCC type acceptance requirements (cabinet emissions) has a resultant electromagnetic exposure level that is several orders of magnitude below the maximum permissible EME level. This ensures that cabinet level emissions from individual, type
45、accepted equipment, that is properly installed and maintained, does not constitute an EME hazard. This does not imply that a particular site, that has type accepted equipment, is in fact a non- hazardous transmitter installation. The FCC limits for cabinet RF emissions assures that unintentional cab
46、inet emissions, at distances suitable for maintenance activities, are below the FCC MPE limits. However, the levels of intentional emission must be characterized by means of computation or measurement, to determine what precautions and work practices must be adhered to for each transmitter site. 6 C
47、opyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-EIA TSB72-ENGL 1998 323Lib00 Ob14232 887 W ENTER W FREQUENCY IN MHz 3.00 6.00 9.00 12.00 15.00 18.00 21 .o0 24.00 27.00 30.00
48、t5b92 w ENTE VERTICAL POL. COMPUTED FCC WORKtK FCC GEN POP MEASURED POWER WORKER MPE PERCENT GEN POP. MPE PERCENT POWER, dBrn DENSIN, mW/cq. cm IN mWlsq. cm OF FCC MPE IN mW/sq. crn OF FCC MPE -13.00 1.64E-05 100.00 1.64E-05 20.00 8.18E-05 -13.00 1.64E-05 25.00 6.54E-05 5.00 . 3.27E-04 -13.00 1.64E-
49、05 11.11 1.47E-04 2.22 7.36E-04 1.31 E-O3 -13.00 1.64E-05 4.00 4.09E-04 0.80 2.04E-03 -13.00 1.64E-05 2.78 5.89E-04 0.56 2.94E-03 -13.00 1.64E-05 6.25 2.62E-04 1.25 -13.00 1.64E-05 2.04 8.02E-04 0.41 4.01 E-O3 -13.00 1.64E-05 1.56 1.05E-03 0.31 5.23E-03 -13.00 1.64E-05 1.23 1.32E-03 0.25 6.62E-03 -1 3.00 1.64E-05 1 .o0 1.64E-03 0.20 8.18E-03 APPENDIX A W ENTER W HORIZONTAL POL. FREQUENCY MEASURED
