Home' RTCA Documents for Review : DO-262D Contents Appendix D
© RTCA, 2018
A transceiver capable of multi-carrier operation, including any associated PA and
output filter, shall satisfy the requirements of TABLE D2-6 with a 4 dB relaxation when
transmitting two modulated carriers each of which is at the maximum single-carrier
power permitted by Section 126.96.36.199.2.1.2 or one-half the maximum output power of the
transceiver, including PA, whichever is less. Both carriers shall be on assignable
carrier frequencies within the band fTMN to fTMX. The emission that does not fall
within the band 0.99675 fTMN to 1.00325 fTMX or the band 0.99675 fRMN to 1.00325
fRMX shall not exceed the values TABLE D2-6 more than 4 dB.
The emission that falls within the band 0.99675 fTMN to 1.00325 fTMX or the band
0.99675 fRMN to 1.00325 fRMX shall not exceed the two-tone intermodulation signal
level SIMT given in TABLE D2-4.
1. Manufacturers may demonstrate compliance with the standards
established in TABLE D2-6 by testing with CW carriers and
applying a mathematically justifiable spreading factor to account
the modulation rate and the order of the intermodulation product.
Such spreading factor should not increase with IM order faster than
sqrt(k), where k is the lowest order of the IM product capable of
producing products in the specified band.
2. Intermodulation requirements do not apply to AES equipment, or
combination of AES systems as outlined in Section 5.1, that only
transmit on a single carrier frequency.
188.8.131.52.2.1.5 Transmitter Harmonics, Discrete Spurious and Noise Density Limits
NOTES: This section excludes requirements for emissions in the transmit band,
which are covered in Section 184.108.40.206.2.1.9.
When tested with a single modulated signal at the maximum permissible single carrier
level specified by Section 220.127.116.11.2.1.2, the average power output of the composite
harmonic, discrete spurious and noise density, including phase noise, at the
transceiver output shall not exceed the values in TABLE D2-6 except for frequencies
falling within the band .99675 fTMN to 1.00325 fTMX and the band 0.99675 fRMN to
TABLE D2-6 specify power limits at the transceiver output and in EIRP. The EIRP
values may be mathematically adjusted to an equivalent transceiver output value
using the specific antenna configuration specified for the equipment. If the equipment
is configured to operate with several different antennas, the adjustment resulting in the
lowest emission at the transceiver output shall be used. The assumed antenna
gain(s) shall be clearly declared in Section 3 of the system-specific appendix.
The values contained in TABLE D2-6 are based on a standard assumption of 40 dB
isolation between the SATCOM and any GNSS antennas. System-specific
specifications may relax such requirements by increasing the assumed isolation on a
decibel-for-decibel basis up to a maximum isolation of 60 dB. Such a relaxation in
performance shall be accompanied by a specific statement as to the assumed
isolation. The declared isolation may be different for different GNSS systems, for
example GPS and GLONASS. The assumed isolation shall clearly be stated as an
installation requirement in Section 3 of the system-specific appendix.
See Notes on the tables regarding GPS only test requirements where protection for
GLONASS on the same aircraft is not required.
TABLE D2-6 lists the Harmonic, Spurious and Noise Requirements for AES
Equipment with EIRPMAX less than or equal to 15 dBW.
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