February 1, 1996
Square Peg has supplied a modified version of its SCPC channel unit model SCU-2R to satisfy Inmarsats requirement for dual satellite operation of Inmarsat-C. Thirty-one of these Standard-C Remodulator Unit (CRUs) have been delivered and are being installed at Inmarsat Land Earth Stations (LESs) world wide.
The traffic flow is as follows:
Traffic is generated at the originating LES in Std-C format and is presented to a CRU at a 70 MHz ± 18 MHz IF frequency
The CRU demodulates the data and remodulates it on an independent IF frequency
The signal is carried over the primary satellite to a turnaround LES, where it is presented to a second CRU at IF
The second CRU demodulates the data and remodulates it in Std-C format on an independent IF frequency
The signal is carried over the secondary satellite to the Std-C terminals
The Std-C modulation format is unfiltered BPSK at 1200
bps, while that between CRUs is rate ½ coded DMSK at 2400 bps.
The function of a CRU (BPSK to DMSK or vice-versa) is
operator-selectable. The unit can also be operated in BPSK to BPSK or
DMSK to DMSK mode.
Photos of front and rear panel.
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