Comtech EF Data DMD-2050E Spezifikationen Seite 83

  • Herunterladen
  • Zu meinen Handbüchern hinzufügen
  • Drucken
  • Seite
    / 342
  • Inhaltsverzeichnis
  • FEHLERBEHEBUNG
  • LESEZEICHEN
  • Bewertet. / 5. Basierend auf Kundenbewertungen
Seitenansicht 82
DMD2050E Universal Satellite Modem Theory of Operation
MN-DMD2050E Revision 2 3–41
3.11.9.3 Power Limited Links
Carrier-in-Carrier can provide substantial savings even when the original link is power limited.
Spreading the carrier by using a lower modulation and/or FEC along with the latest FEC can
substantially reduce the total power which can then be traded with bandwidth using Carrier-in-
Carrier. The concept is illustrated with the following examples.
The conventional link is using 8-PSK, TPC 3/4:
Switching to an advanced FEC and using a lower order modulation e.g., QPSK,
STANAG TURBO 7/8 increases the total occupied bandwidth, while reducing the total power
equivalent bandwidth:
Now using DoubleTalk Carrier-in-Carrier, the second QPSK, STANAG TURBO 7/8 carrier can be
moved over the first carrier thereby significantly reducing the total occupied bandwidth and total
power equivalent bandwidth when compared to the original side-by-side 8PSK, TPC 3/4 carriers:
Consider this example:
Satellite & Transponder
IS-901 @ 342º W, 22/22 (EH/EH)
Earth Station 1 9.2 m
Earth Station 2 4.5 m
Data Rate 2.048 Mbps / 2.048 Mbps
Seitenansicht 82
1 2 ... 78 79 80 81 82 83 84 85 86 87 88 ... 341 342

Kommentare zu diesen Handbüchern

Keine Kommentare