Validating Carrier-In-Carrier Performance - Radyne DMD50 Installation And Operation Manual

DMD50 Universal Satellite Modem
3.14.11

Validating Carrier-in-Carrier Performance

Carrier-in-Carrier performance can be easily validated by verifying that Eb/No degradation due to
Carrier-in-Carrier is within published specification for the observed Power Spectral Density Ratio.
The following procedure is recommended for validating Carrier-in-Carrier performance:
Step Procedure
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:
MN-DMD50 Revision 4
 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.
Theory of Operation
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