Furuno FELCOM 12, Руководство по обслуживанию

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2-1
2.1 Channel Types
A MES uses the following channels for the communications.
1) NCS Common Channel (NCS CC)
2) CES TDM Channel
3) SES Signalling Channel
4) SES Message Channel
Details of each channel are tabulated below.
NCS Common
Channel
CES TDM
Channel
SES Signalling
Channel
SES Message
Channel
Use
MES signalling
(Line control),
EGC, etc.
MES signalling
(Line control), LES
to MES message
NCS, LES
signalling
(Line control)
MES to LES
message
Contents Refer to section 1.3.
TX method
Continuous
TDM
TDM
(Time Division
Multiplex),
Continuous or on
demand
TDMA
(Time Division
Multiplex Access)
SCPC (Single
Channel Per
Carrier)
Speed
8.64sec/frame
1200
symbols/sec
8.64sec/frame
1200 symbols/sec
1200 symbols/sec,
28 slots
(2nd Gen.SV)
1200
symbols/sec
(2nd Gen.SV)
Packet 640 bytes 640 bytes 15 bytes 128 bytes
Bulletin Board Every frame Every frame - -
Scrambling
Encoding
Unique word 128 symbols 128 symbols 64 symbols 128 symbols
Permuting -
Preamble - - - (192bits)
Signal
process (TX)
Interleaving -
Number of Symbols 10368 symbols 10368 symbols 316 symbols 10368
TDM: Time division multiplex. A process for transmitting two or more channel
signals simultaneously to MES over a common channel path by using
successive time intervals (time slots) for different channels.
TDMA:Time division multiplex access. A system which allows a plural number of
MES to access an LES (NCS) over a single transmission line by assigning
each MES a time slot on the TDM channel in which to transmit over.
SCPC: Single channel per carrier. Enables assignment of channel for a call.
NCS
LES
MES
Satellite
NCS Common Channel
6GHz
1.5GHz
SES Signalling Channel
6GHz
4GHz
SES Message Channel
1.6GHz
1.6GHz
4GHz
4GHz
CES TDM Channel
1.5GHz
Figure 2-1
Chapter 2 Channel Types and Signal
Processing