AMT-70/AMT-73/AMT-75 Installation and Operation
Figure 6: Allocated Bandwidth and Eb/No for Viterbi and Viterbi + Reed Solomon
3.3 Modem Applications and Typical Operating Scenarios
The AMT-70 modem series supports a wide variety of coding schemes and data interfaces allowing its
use in a variety of applications. An overview of some of the common applications and modes are
outlined in this section of the manual. The AMT-73 is primarily designed to operate in the SCPC mode,
although it can be optioned to operate as a DVB Modulator or Data Broadcast Modulator as well.
3.3.1 DVB (MPEG-2) Modulator
The AMT-70 can be configured as a DVB Modulator carrying MPEG-2 traffic. The specific model
number for the modulator-only product is AMT70 (TX only) for DVB-S or DVB-DSNG and AMT-75 for a
47
Transmission Method
Viterbi & Viterbi R/S
Channel Spacing
(Rounded)
E
b
/N
0
@ 10
-07
(Typical) dB
INTELSAT SYSTEM
Viterbi Viterbi + R/S Viterbi Viterbi + R/S
2048 kbps, QPSK, rate 1/2 2870 kHz 3025 kHz 6.5 4.4
2048 kbps, QPSK, rate 3/4 1915 kHz 2085 kHz 7.8 5.9
2048 kbps, QPSK, rate 7/8 1640 kHz 1785 kHz 9.0 6.9
256 kbps, QPSK, rate 1/2 360 kHz 390 kHz 6.5 4.4
256 kbps, QPSK, rate 3/4 240 kHz 260 kHz 7.8 5.9
256 kbps, QPSK, rate 7/8 205 kHz 225 kHz 9.0 6.9
128 kbps, QPSK, rate 1/2 180 kHz 195 kHz 6.5 4.4
128 kbps, QPSK, rate 3/4 120 kHz 130 kHz 7.8 5.9
128 kbps, QPSK, rate 7/8 105 kHz 115 kHz 9.0 6.9
128 kbps, BPSK, rate 1/2 360 kHz 390 kHz 6.5 4.4
64 kbps, QPSK, rate 1/2 90 kHz 100 kHz 6.5 4.4
64 kbps, QPSK, rate 3/4 60 kHz 65 kHz 7.8 5.9
64 kbps, QPSK, rate 7/8 55 kHz 60 kHz 9.0 6.9
64 kbps, BPSK, rate 1/2 180 kHz 180 kHz 6.5 4.4
32 kbps, QPSK, rate 1/2 45 kHz 50 kHz 6.5 4.4
32 kbps, QPSK, rate 3/4 25 kHz 30 kHz 7.8 5.9
32 kbps, BPSK, rate 1/2 90 kHz 100 kHz 6.5 4.4
Viterbi with RS (204,188)
DVB SYSTEM
Actual
Code Rate
Channel
Spacing
E
b
/N
0
@ 10
-11
BER (Quasi Error
Free) dB
DVB-S 20 Mbps, QPSK, Rate 1/2 0.46 30.4 MHz 4.1
DVB-S 20 Mbps, QPSK, Rate 2/3 0.61 23.0 MHz 4.6
DVB-S 20 Mbps, QPSK, Rate 3/4 0.69 20.3 MHz 5.1
DVB-S 20 Mbps, QPSK, Rate 5/6 0.77 18.2 MHz 5.6
DVB-S 20 Mbps, QPSK, Rate 7/8 0.81 17.3 MHz 6.0
DVB-DSNG 40 Mbps, 8PSK, Rate 2/3 0.614 30.4 MHz 6.5
DVB-DSNG 40 Mbps, 8PSK, Rate 5/6 0.77 24.2 MHz 7.9
DVB-DSNG 40 Mbps, 8PSK, Rate 8/9 0.82 22.8 MHz 8.4
DVB-DSNG 60 Mbps, 16QAM, Rate 3/4 0.69 30.4 MHz 8.6
DVB-DSNG 60 Mbps, 16QAM, Rate 7/8 0.81 25.9 MHz 10.3
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