CDM-710 Broadcast Satellite Modem
Revision 11
Forward Error Correction Options MN/CDM710.IOM
7–3
Another useful parameter is the occupied bandwidth is the bandwidth between -10 dB
points of the power spectral density, which are approximately:
Occupied Bandwidth
=
1.19
x
Symbol Rate, for 35% Rolloff
=
1.15
x
Symbol Rate, for 25% Rolloff
= 1.12 x Symbol Rate, for 20% Rolloff
provides the Eb/No, spectral efficiency and occupied bandwidth for the CDM-710.
outline these parameters per the modem’s DVB schemes.
Figure 7-1
through
Figure 7-7
illustrate the error performance characteristics. To convert
Es/No to Eb/No:
Eb/No = Es/No - 10xLog(Spectral Efficiency)
Table 7-1. Eb/No, Spectral Efficiency and Occupied Bandwidth*
Mode
Type FEC Code
Inner
Code
Rate
Eb/No
at QEF
Spectral
Efficiency
(bps/Hz)
Normalized
Symbol Rate (=
Bit Rate x)
Occupied *
Bandwidth for
10 Mbps (35%
Rolloff)
DVB-S QPSK
Conv+RS 1/2 4.5
0.921569 1.085
12.913
QPSK Conv+RS 2/3 5.0 1.228758 0.814
9.685
QPSK Conv+RS 3/4 5.5 1.382353 0.723
8.609
QPSK Conv+RS 5/6 6.0 1.535948 0.651
7.748
QPSK Conv+RS 7/8 6.4 1.612745 0.620
7.379
DVB-DSNG 8-PSK Conv+RS 2/3 6.9 1.843137 0.543
6.456
8-PSK Conv+RS 5/6 8.9 2.303922
0.434
5.165
8-PSK Conv+RS 8/9 9.4 2.457516
0.407
4.842
16-QAM Conv+RS 3/4 9.0 2.764706
0.362
4.304
16-QAM Conv+RS 7/8 10.7 3.225490
0.310
3.689
* Taken at the -10 dB points on the plot of power spectral density, the occupied bandwidth is 1.19 x
Symbol Rate for 35%, and 1.15 x Symbol Rate for 25%.
Содержание CDM-710
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Страница 26: ...CDM 710 Broadcast Satellite Modem Revision 11 Preface MN CDM710 IOM xx Notes ...
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Страница 144: ...CDM 710 Broadcast Satellite Modem Revision 11 Ethernet Management MN CDM710 IOM 6 24 Notes ...
Страница 230: ...CDM 710 Broadcast Satellite Modem Revision 11 Appendix A MN CDM710 IOM A 56 Notes ...
Страница 236: ...CDM 710 Broadcast Satellite Modem Revision 11 Eb No Measurement MN CDM710 IOM B 6 Notes ...
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