Comtech EF Data SDM-9000 - Manual (Page 34)

Introduction SDM-9000 Satellite Modem
1–12 Rev. 4
1.4 BER Performance Specifications
The bit energy-to-noise ratios (E
b
/N
0
) required to achieve 10 -3 to 10 -10 Bit Error Rates
(BERs) are listed in Tables 1-2 through 1-4. The BER performance curves are shown in
the following figures:
Figure Modulation
1-4 QPSK
1-5 QPSK (with Reed-Solomon)
1-6 8PSK (with Reed-Solomon)
1-7 16QAM (with Reed-Solomon)
1.4.1 Viterbi Decoder BER (QPSK)
The Viterbi specifications for the E
b
/N
0
required to achieve 10 -3 to 10 -8
BER for different
coding configurations are shown in Table 1-2. All values are for operation in QPSK
mode.
Performance measurements are recorded with transmit and receive IF connected
back-to-back through an additive white Gaussian noise channel. Refer to Figure 1-4 for
the Viterbi BER curves.
Table 1-2. Viterbi Decoder BER Data
Specification
BER 1/2 Rate 3/4 Rate 7/8 Rate
10 -3 4.2 dB 5.2 dB 6.4 dB
10 -4 4.8 dB 6.0 dB 7.2 dB
10 -5 5.4 dB 6.7 dB 7.9 dB
10 -6 6.0 dB 7.5 dB 8.6 dB
10 -7 6.6 dB 8.2 dB 9.2 dB
10 -8 7.2 dB 8.8 dB 9.9 dB
Typical
BER 1/2 Rate 3/4 Rate 7/8 Rate
10 -3 3.8 dB 4.8 dB 6.0 dB
10 -4 4.2 dB 5.5 dB 6.6 dB
10 -5 4.9 dB 6.1 dB 7.3 dB
10 -6 5.5 dB 6.7 dB 8.0 dB
10 -7 6.1 dB 7.6 dB 8.6 dB
10 -8 6.7 dB 8.2 dB 9.3 dB