ELPRO RT2e, Руководство по эксплуатации

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EN - 17 Wireless Sensor RT2e
EL6107E
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6.3 FCC
In the USA, the FCC (Federal Communications Commission) regulates the use of frequencies for RF
equipment. CFR 47 part 15 (Code of Federal Regulations) covers the unlicensed ISM bands. This is
usually referred to as FCC part 15. All equipment must be certified with the FCC with the issuance of a
Grant of Authorization by the FCC. When the product is approved, the FCC issues an identification
number which the product must be marked with.
The part 15 sections for ISM band radios are:
- 15.19 / RSS-210: Manual requirements
- 15.35: General rules for certification measurements
- 15.105: Manual requirements
- 15.109: Radiated emission limits for unintentional radiators
- 15.205: Restricted bands of operation
- 15.209: Radiation limits for intentional radiators
- 15.247: Frequency Hopping and Spread Spectrum (FHSS), operation within the bands 902 - 928MHz,
2400 - 2483.5 MHz
Spurious emissions
and restricted
bands A large part of the FCC Part 15 is about the limit of spurious emissions (harmonic component) and
restricted bands. The main concept behind part 15 is that a general set of rules must be followed, but with
exceptions for different application and frequency bands.
Emissions are divided into two parts:
- Unintended radiators, like receivers and transmitters in standby or other radiators requirements are
given in 15.109
- Intended radiators, like active transmitters requirements are given in 15.209
There are a number of restricted frequencies according to 15.205 which cannot be used for active
transmissions, but spurious emissions can be produced. The levels are given in EIRP, Electrical Field
Strength Power, at a distance of 3 meters
White Paper 915MHz band
Section 15.249 gives the opportunity to use the 902-928MHz band with an output power of 50mV/m at 3
meters or -1.2dBm. The harmonics are limited to 500uV/m or -41.2dBm. This band is commonly referred
to as the 915MHz band in the USA. There are no restrictions on duty cycle or the application.
Even higher output power can be used according to section 15.247. This implies the use of frequency
hopping. The following requirements must be fulfilled for the use of the 902-928MHz band under section
15.247:
- Hopping channels shall be separated by minimum 25 kHz or the 20dB bandwidth of the hopping
channel, whichever is greater.
- The system shall hop to channel frequencies that are selected at the system hopping rate from a
pseudorandomly ordered list of hopping frequencies.
- If the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50
hopping frequencies and the average time of occupancy on any frequency shall not be greater than
0.4 seconds within a 20 second period.
- If the 20 dB bandwidth of the hopping channel is 250 kHz or greater, the system shall use at least 25
hopping frequencies and the average time of occupancy on any frequency shall not be greater than
0.4 seconds within a 10 second period.
- The maximum allowed 20 dB bandwidth of the hopping channel is 500 kHz.
- Maximum peak conducted output power is 1W in the 902-928MHz band if more than 50 hopping
channels are used. The limit is 0.125W for 25 to 50 hopping channels.
Frequency Electrical Field Strength EIRP
216-960MHz 200mV/m -49.2dBm