Summary Of Specifications - Comtec CDM-840 Installation And Operation Manual

CDM-840 Remote Router
Appendix D
•
ACM maximizes throughput not only when Eb/No varies due to atmospheric conditions, but
will also mitigate the effects of other impairments, such as antenna pointing error, excessive
phase noise and certain types of interference. However, rapidly fluctuating impairments (i.e.,
~ less than 1 second) such as scintillation at low antenna look-angles at C-band will generally
not be improved by ACM.
D.6

Summary of Specifications

System type
Symbol Rate Range
Interface
Remote SNR reporting
Max span of data rate
Switch point (decreasing SNR)
Switch point hysteresis
Max fading rate
Max ModCod update rate
Configurable parameters
System latency
Monitored parameters
Modulation Code Rate
BPSK 0.488
QPSK 0.533
QPSK 0.631
QPSK 0.706
QPSK 0.803
8-QAM 0.642
8-QAM 0.711
8-QAM 0.780
16-QAM 0.731
16-QAM 0.780
16-QAM 0.829
16-QAM 0.853
Adaptive Coding and Modulation, using BPSK, QPSK, 8-QAM , 16-QAM and
VersaFEC short-block LDPC coding - total of 12 ModCods
16 ksps to 4500 ksps
10/100 BaseT Ethernet, with auto-negotiated Congestion Control
Automatically reported from remote modem – built in function at the physical
layer – requires no additional overhead
7:1 over range of adaptation
Corresponds to SNR (Es/No) that gives BER = 5 x 10
0.3 dB
Approximately 1 dB/second (higher if Target Eb/No margin > 1 dB)
1 update every 2 seconds
Minimum and Maximum ModCod (ModCod0 through ModCod11)
•
Remote Demod Unlock Action: Maintain current ModCod
•
Target SNR margin (0 to 4.5 dB, 0.5 dB steps)
•
34 milliseconds max (not including WAN buffer, or satellite path)
Tx and Rx ModCods
•
Local and Remote SNR
•
(-3.0 dB to +22.0 dB, 0.1 dB resolution, +/- 0.5 dB accuracy)
Config and monitor menus displaying data rate, modulation and code rate update
•
dynamically with ModCod
Typical Eb/No, for
Spectral Efficiency,
BER = 5 x 10
bps/Hz
0.49
1.07
1.26
1.41
1.61
1.93
2.13
2.34
2.93
3.12
3.32
3.41
D–11
(margin set to 0 dB)
-8
Go to minimum ModCod
Min. Data Rate,
ACM mode
-8
(dB) (kbps)
2.4 16.00
2.2 17.07
2.7 20.19
3.4 22.577
3.8 25.69
4.6 30.83
5.2 34.14
5.6 37.44
6.5 46.80
7.1 49.92
7.7 53.04
8.1 54.60
MN-CDM840
Revision 3
Max. Data Rate,
ACM mode
(Mbsp)
2.19
4.80
5.67
6.34
7.22
8.67
9.60
10.53
13.26
14.04
14.91
15.35