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F.2.7
Validate Carrier-in-Carrier Performance
You may easily validate Carrier-in-Carrier performance by verifying that Eb/No degradation due to
Carrier-in-Carrier is within published specification for the observed Power Spectral Density Ratio.
Comtech EF Data recommends that you do these steps to validate CnC performance:
Step
Setup a conventional side-by-side link of the desired Eb/No:
1
Example Link:
Now relocate one of the carriers on top of the other carrier:
2
Calculate change in Eb/No and verify against specification.
3
Example Link:
Appendix F
Carrier-in-Carrier should be OFF.
•
Record the Eb/No as displayed by the Modems.
•
Observe the 2 carriers on a spectrum analyzer and record the PSD ratio.
•
Full duplex 512 kbps, QPSK, LDPC 2/3 circuit between 4.6 m and 2.4 m antennas
•
Recorded Eb/No = 2.6 dB (at both modems)
•
PSD Ratio = 1.2 dB (measured at larger Antenna)
•
Enable Carrier-in-Carrier.
•
Record the Eb/No as displayed by the Modems.
•
Recorded Eb/No = 2.4 dB
•
Change in Eb/No = 0.2 dB
•
Eb/No Degradation (Spec.) at 1.2 dB PSD = 0.3 dB
•
Modem performance is within spec
•
CDM-425 Advanced Satellite Modem
Task
F–18
Revision 0
MN-CDM-425
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