RF exposure calculation

FCC ID: 2AJMW-BTSPK26

RF Exposure Info

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FCCID_3443702

BST1705777170001Y-ER-2 RF Exposure evaluation FCCID: 2AJMW-BTSPK26 According to 447498 D01 General RF Exposure Guidance v06 4.3. General SAR test exclusion guidance 4.3.1. Standalone SAR test exclusion considerations a) For 100 MHz to 6 GHz and test separation distances ≤ 50 mm, the 1-g and 10-g SAR test exclusion thresholds are determined by the following: [(max. power of channel, including tune-up tolerance, mW) / (min. test separation distance, mm)] · [√f(GHz)] ≤ 3.0 for 1-g SAR, and ≤ 7.5 for 10-g extremity SAR, 30 where • f(GHz) is the RF channel transmit frequency in GHz •Power and distance are rounded to the nearest mW and mm before calculation31 •The result is rounded to one decimal place for comparison •The values 3.0 and 7.5 are referred to as numeric thresholds in step b) below The test exclusions are applicable only when the minimum test separation distance is ≤ 50 mm, and for transmission frequencies between 100 MHz and 6 GHz. When the minimum test separation distance is < 5 mm, a distance of 5 mm according to 4.1 f) is applied to determine SAR test exclusion. 30 This is equivalent to the formula written as: [(max. power of channel, including tune-up tolerance, mW)/(60/√f(GHz) mW)]·[20 mm/(min. test separation distance, mm)] ≤ 1.0 for 1-g SAR; also see Appendix A for approximate exclusion threshold numerical values at selected frequencies and distances. eirp = pt x gt = (EXd)2/30 where: pt = transmitter output power in watts, gt = numeric gain of the transmitting antenna (unitless), E = electric field strength in V/m, --- 10((dBuV/m)/20)/106 d = measurement distance in meters (m)---3m So pt = (EXd)2/30 x gt

BST1705777170001Y-ER-2 RF Exposure evaluation Copied from the FCC test report: clause9.4 Maximum Peak Output Power Test Result: For GFSK Frequency Measured Value Output Power Limit Channel MHz dBm mW mW Low Channel 2402 -0.15 0.97 125 Middle Channel 2441 2.62 1.83 125 High Channel 2480 3.70 2.34 125 For Pi/4 QDPSK Frequency Measured Value Output Power Limit Channel MHz dBm mW mW Low Channel 2402 -2.90 0.51 125 Middle Channel 2441 1.06 1.28 125 High Channel 2480 2.10 1.62 125 For 8DPSK Frequency Measured Value Output Power Limit Channel MHz dBm mW mW Low Channel 2402 -3.00 0.50 125 Middle Channel 2441 1.10 1.29 125 High Channel 2480 2.14 1.64 125 Note: the antenna gain of 1dBi less than 6dBi maximum permission antenna gain value based on 1 watt peak output power limit. Then we choose Normal mode channel as the worst case of Maximum Peak Output Power: Frequency Measured Value Output Power Limit Channel MHz dBm mW mW Low Channel 2402 -0.15 0.97 125 Middle Channel 2441 2.62 1.83 125 High Channel 2480 3.70 2.34 125 EIRP/ dBm= Conducted Max Output Power/ dBm+ Antenna gain /dBi. Since the distance from the internal BT-antenna to the outer is more than 10mm, we choose the min. test separation distance = 5mm

BST1705777170001Y-ER-2 General RF Exposure: (0.97mW )/5.0mm)x √2.402 GHz = 0.301 (1.83mW )/5.0mm)x √2.441 GHz = 0.571 (2.34mW )/5.0mm)x √2.480 GHz = 0.737 SAR requirement: S=3.0 General RF Exposure<3 Then SAR evaluation is not required


Document Created: 2017-06-26 16:50:35
Document Modified: 2017-06-26 16:50:35
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