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22、. TSB-92-A ii THIS PAGE INTENTIONALLY LEFT BLANK TSB-92-A iii TABLE OF CONTENTS 1. INTRODUCTION 1 1.1. SCOPE. 1 2. REFERENCES. 1 3. FCC ELECTROMAGNETIC EMISSION LIMITS. 1 4. LIMIT CASE ANALYSIS 3 4.1. CALCULATION OF EME LEVEL BASED ON THE FCC LIMIT OF -13 DBM FOR EACH OF THE TRANSMITTER HARMONICS (1
23、-10) 3 4.2. EXAMPLE SPREADSHEET CALCULATIONS 3 4.3. CALCULATIONS AT REPRESENTATIVE FREQUENCIES 3 MHZ 2 GHZ. 4 4.4. MEASUREMENT METHOD. 5 5. TRANSMITTER SITE CONSIDERATIONS. 5 5.1. SITE COMPLIANCE 5 6. SUMMARY. 6 ANNEX A A-1 ANNEX B B-1 DOCUMENT REVISION HISTORY Version Date Description TSB-92 July 1
24、998 Initial release TSB-92A October 2008 Removed references to vehicular application and updated document style. TSB-92-A iv FOREWORD This foreward is not part of this Telecommunications Systems Bulletin (TSB) This TSB is the product of work undertaken by the Electromagnetic Energy (EME) working gro
25、up of the TIA TR8.17 RF Exposure subcommittee. The subcommittee addresses Radio Frequency Exposure matters. TR8.17 is a subcommittee of TIA TR8 Mobile and Personal Private Radio Standards Engineering Committee. This TSB was revised and approved for publication at the October 16, 2008 meeting of TR8.
26、17. The motion to publish was ratified at the January 22, 2009 meeting of TR8.17. There are two annexes, Annex A and Annex B, in this TSB and both are informative. TSB-92-A v Patent Identification The readers attention is called to the possibility that using this document might necessitate the use o
27、f one or more inventions covered by patent rights. By publication of this document no position is taken with respect to the validity of those claims or any patent rights in connection therewith. The patent holders so far identified have, we believe, filed statements of willingness to grant licenses
28、under those rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such licenses. The following patent holders and patents have been identified in accordance with the TIA intellectual property rights policy: None identified TIA is not be responsible for iden
29、tifying patents for which licenses might be referenced by this document or for conducting inquiries into the legal validity or scope of those patents that are brought to its attention. TSB-92-A vi THIS PAGE INTENTIONALLY LEFT BLANK TSB-92-A 1 1. Introduction 1.1. Scope This TSB establishes and docum
30、ents methods and procedures of evaluation to establish compliance of fixed station cabinet emission levels with respect to the Federal Communications Commission (FCC) electromagnetic exposure (EME) limits. Specifically the EME characterization is of box level equipment only, e.g., a fixed station, c
31、ontrol station, or similar equipment. This TSB is not a substitute for a complete transmitter site environmental assessment (EA) by means of computational methods or site measurement or a combination of these two means. A limit case analysis based on the 47 CFR part 90 certification requirements for
32、 spurious emissions limits included herein shows that certified equipment at the box level is within the FCC maximum permissible exposure (MPE) limits. 2. References This Telecommunications System Bulletin contains only informative information. There are references to TIA standards which contain nor
33、mative elements. These references are primarily to indicate the methods of measurement contained in those documents. At the time of publication, the edition indications were valid. All standards and bulletins are subject to revision, and parties to agreements based on this document are encouraged to
34、 investigate the possibility of applying the most recent edition of the standard or bulletin indicated in Section 3. ANSI and TIA maintain registers of currently valid national standards published by them. There are references to FCC rules. The Federal Code of Regulations (CFR) is subject to revisio
35、n. The Government Printing Office (GPO) maintains a listing of the latest published titles. 3. FCC Electromagnetic Emission Limits Controlled and general population RF Exposure Limits are shown in Table 1, below. The RF Exposure Limits shown in Table 1 are the limits adopted by the FCC. The RF expos
36、ure limits adopted by the FCC are generally based on recommendations from the National Council on Radiation Protection and Measurements (NCRP) Report No. 86 and the American National Standards Institute (ANSI/IEEE) C95.1-1992.11NCRP Report No. 86, “Biological Effects and Exposure Criteria for Radiof
37、requency Electromagnetic Fields“, sections 17.4.1, 17.4.1.1, 17.4.2 and 17.4.3; copyright NCRP, 1986, Bethesda, Maryland 20814. ANSI/IEEE C95.1-1992, “IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz”, Section 4.1; copyright 1
38、992 by the Institute of Electrical and Electronics Engineers, Inc., New York, New York 10017. TSB-92-A 2 Table 1 MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMITS2(A) Limits for Occupational/Controlled Exposure Frequency Electric Field Magnetic Field Power Density Averaging Time Range Strength (E) Strength
39、(H) (S) (MHz) (V/m) (A/m) (mW/sq. cm) (minutes) 0.3-3.0 614 1.63 (100)* 6 3.0-30 1842/f 4.89/f (900/f2)* 6 30-300 61.4 0.163 1.0 6 300-1500 - - f/300 6 1500-100,000 - - 5 6 (B) Limits for General Population/Uncontrolled Exposure Frequency Electric Field Magnetic Field Power Density Averaging Time Ra
40、nge Strength (E) Strength (H) (S) (MHz) (V/m) (A/m) (mW/sq. cm) (minutes) 0.3-1.34 614 1.63 (100)* 30 1.34-30 824/f 2.19/f (180/f2)* 30 30-300 27.5 0.073 0.2 30 300-1500 - - f/1500 30 1500-100,000 - - 1.0 30 f = frequency in MHz *Plane-wave equivalent power density 2See 47 CFR 1.1310. TSB-92-A 3 4.
41、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 result in an equipment level EME that is compliant to the MPE limits as set forth in 47 CFR 1.1310. 4.1. Calculation of EME level bas
42、ed on the FCC limit of -13 dBm for each of the transmitter harmonics (1-10). The limit case calculation will compute the resultant EME level, as a percent of the MPE level, of a transmitter that exhibits the maximum allowable cabinet emission limits as defined in 47 CFR 90.210. This maximum level is
43、 a spurious emission that is attenuated by at least 43 + 10 log(P) dB, with P being the transmitter average power in watts or equivalently -13 dBm. The cabinet emissions are considered to be emitted from a point source. As such it is necessary to define a distance at which the power density will be
44、calculated. A distance of 20 cm is used based on the ANSI/IEEE C95.3-2002 “Recommended Practice for the Measurement of Potentially Hazardous Electromagnetic Fields RF and Microwave” recommendation of a minimum separation distance of 20 cm between the probe and the perturbing object. This will allow
45、controlled population to be sufficiently close to the equipment to allow direct observation or normal service interface through a terminal device or similar equipment. 4.2. Example spreadsheet calculations Calculation method: 1. Compute the power density, S, using equation 1, for each harmonic at th
46、e maximum allowable FCC radiated level (-13 dBm), at the specified distance, 20 cm, for the horizontal polarization, “where Prad is the power radiated”. S = (Pradx 1.64)/( x r2) mW/cm2, r=20 cm (1) Pradis the radiated power (mW) r is the minimum working distance (cm) 2. Compute percent of MPE for ea
47、ch harmonic using equation 2. %MPE(fn) = 100 x S(fn)/MPE(fn) (2) MPE(fn) is the allowable MPE for each transmitter harmonic , n = 1 to 10; S(fn) is the power density for each transmitter harmonic, n = 1 to 10; TSB-92-A 4 3. %MPE(h) = Sum of %MPE(fn), n = 1-10. %MPE(h) is the percent of the maximum p
48、ermissible exposure in the horizontal polarization 4. Repeat steps 1-3 for vertical polarization. 5. Total %MPE = %MPE(h) + %MPE(v) 4.3. Calculations at representative frequencies 3 MHz 2 GHz Tables showing the complete set of calculations (horizontal and vertical polarization) for each frequency an
49、d its harmonics are included in Annex A. Table 2 below shows the highest level computed for each of the various Fundamental Frequencies shown in Annex A. Table 1 Maximum Resultant Controlled and General Population Percentage of FCC MPE limits for each Fundamental Frequency shown in Annex A Fundamental Frequency (MHz) Controlled Population % MPE General Population % MPE 3 1.26E-02 6.30E-02 30 3.27E-02 1.64E-01 450 8.58E-03 4.29E-02 900 6.98E-03 3.49E-02 1900 6.54E-03 3.27E-02 The highest (worst case) computed level, as shown in Table 2, above at a Fundamental F
