5.2 EMC Regulations for 2.4 GHz
5.2.1 ETSI EN 300-328 Emission Limits for the 2400-2483.5 MHz Band
Based on ETSI EN 300-328 the allowed maximum fundamental power for the 2400-2483.5 MHz band is 20 dBm EIRP. For the unwan-
ted emissions in the 1 GHz to 12.75 GHz domain the specified limit is -30 dBm EIRP.
5.2.2 FCC15.247 Emission Limits for the 2400-2483.5 MHz Band
FCC 15.247 allows conducted output power up to 1 Watt (30 dBm) in the 2400-2483.5 MHz band. For spurious emissions the limit is
-20 dBc based on either conducted or radiated measurement, if the emission is not in a restricted band. The restricted bands are speci-
fied in FCC 15.205. In these bands the spurious emission levels must meet the levels set out in FCC 15.209. In the range from
960 MHz to the frequency of the 5th harmonic it is defined as 0.5 mV/m at 3 m distance (equals to -41.2 dBm in EIRP).
In case of operating in the 2400-2483.5 MHz band the 2nd, 3rd and 5th harmonics can fall into restricted bands so for those the
-41.2 dBm limit should be applied. For the 4th harmonic the -20 dBc limit should be applied.
5.2.3 Applied Emission Limits
The overall applied limits are shown in the table below. For the harmonics that fall into the FCC restricted bands, the FCC 15.209 limit
is applied, and the ETSI EN 300-328 limit is applied for the rest.
Table 5.3. Applied Limits for Spurious Emissions
Harmonic
Frequency
Limit
2nd
4800~4967 MHz
-41.2 dBm
3rd
7200~7450.5 MHz
-41.2 dBm
4th
9600~9934 MHz
-30 dBm
5th
12000~12417.5 MHz
-41.2 dBm
5.3 Relaxation with Modulated Carrier
Depending on the applied modulation scheme, and the Spectrum Analyzer settings specified by the relevant EMC regulations, the
measured power levels are usually lower compared to the results with unmodulated carrier. These differences have been measured
and used as relaxation factors on the results of the radiated measurement performed with unmodulated carrier. This way, the radiated
compliance with modulated transmission can be evaluated.
In this case, both the ETSI EN 300-328 and the FCC 15.247 regulations define the following Spectrum Analyzer settings for measuring
the unwanted emissions above 1 GHz:
• Detector: Average
• RBW: 1 MHz
The table below shows the relative levels of the measured modulated signals compared to the unmodulated levels with the above
Spectrum Analyzer settings in case of the supported modulation schemes.
Table 5.4. Measured Relaxation Factors for the Supported Modulation Schemes
Applied Modulation
(Packet Length:
255 bytes)
BLE Coded PHY:
125 Kb/s (PRBS9) [dB]
BLE Coded PHY:
500 Kb/s (PRBS9) [dB]
BLE 1M PHY: 1 Mb/s
(PRBS9) [dB]
BLE 2M PHY: 2 Mb/s
(PRBS9) [dB]
2nd harmonic
-2.7
-3.1
-3.3
-9.1
3rd harmonic
-4.8
-5.2
-5.2
-10.7
4th harmonic
-5.5
-6.5
-6.7
-11.9
5th harmonic
-6.3
-6.5
-6.7
-11.4
UG524: xG24 Dev Kit User's Guide
Radio
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