Comtech EF Data Vipersat SLM-5650A, Installation And Operation Manual

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SLM-5650A Satellite Modem
Revision 10
Appendix H G–26 MN-SLM-5650A
Power Spectral Density (PSD):
Power Spectral Density (PSD) is the signal power per unit bandwidth: dBW/Hz or dBm/Hz
For example: Signal power = 20 dBm
Signal bandwidth = 5 MHz
PSD = 20 – 10
log
(5,000,000) = -46.99 dBm / Hz
PSD Ratio:
Ratio of Power Spectral Density (PSD) of the interfering carrier to the desired carrier.
If looking at the two carriers side-by-side on a
spectrum analyzer:
Quasi Error Free (QEF):
Quasi Error Free (QEF) corresponds to PER ~10
-7
PER (packet error rate) is based upon a 188-byte MPEG frame size
Spectral Efficiency (SE):
Ratio of the Data Rate to the Symbol Rate.
Symbol Rate & Data Rate:
Symbol Rate and Data Rate are related:
•
DR = SR * SE [Data Rate = Symbol Rate * Spectral Efficiency]
•
SR = DR / SE [Symbol Rate = Data Rate / Spectral Efficiency]