G.4.5.4 Commission and Deploy Carrier-in-Carrier
Prior to commissioning a Carrier-in-Carrier link, it is critical that the link is fully tested in non
Carrier-in-Carrier mode and all system issues including external interference, antenna pointing,
cabling, SSPA backoff are resolved. Only after the link is robust, should you attempt turning on
Carrier-in-Carrier. The following steps are recommended for Carrier-in-Carrier commissioning and
deployment:
Step
Task
1
Turn ON the carrier at Site A. Carrier from Site B is OFF. CnC function is OFF at both sites.
Using a spectrum analyzer, measure Co+No/No at the input to the modem at Site A.
Using a spectrum analyzer, measure Co+No/No at the input to the modem at Site B.
Measure/record Eb/No at Site B. Make sure there is sufficient margin to account for CnC.
Measure/record Receive Signal Level (RSL) at Site B.
2
Turn OFF the carrier at Site A. Turn ON the carrier at Site B. CnC function is OFF at both sites.
Using a spectrum analyzer, measure Co+No/No at the input to the modem at Site A.
Using a spectrum analyzer, measure Co+No/No at the input to the modem at Site B.
Measure/record Eb/No at Site A. Make sure there is sufficient margin to account for CnC.
Measure/record RSL at Site B.
3
Using Co+No/No readings calculate PSD ratio at Site A and Site B. If it is not within specification, make
necessary adjustments to bring it within specification and repeat measurements in Step (1) and (2).
Also verify that the RSL is within spec.
4
Now without changing the transmit power levels, turn ON both the carriers (on the same frequency) and
turn CnC ON.
Measure/record Eb/No at Site A and B.
Measure/record RSL at Site A and B.
Now compare Eb/No in presence of 2 over lapping carriers with CnC with Eb/No when only 1
5
The test can be repeated for different PSD ratio and Eb/No.
DoubleTalk Carrier-in-Carrier Option
CDM-570A/570AL Satellite Modem with Optional Packet Processor
carrier was ON. Eb/No variation should be within spec for that modulation, FEC and PSD ratio.
G–17
Revision 5
MN-CDM570A