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SDM-300A Satellite Modem
C.4.1
Performance with Noise, Viterbi Decoder, and Open Network
Mode
Refer to Figure C-1 for the Viterbi BER curves.
Table C-7 lists the Viterbi specifications for the E
BER for different coding configurations. All values are for operating in QPSK mode.
Without coding, the modem provides QPSK operation within 0.8 dB of theoretical for
BER in the range 10
and receive IF connected back-to-back through an additive white Gaussian noise channel.
Table C-7. Viterbi Decoder with Open Network BER Data
Rev. 4
-1
to 10
-6
. Performance measurements were recorded with transmit
E
/N
(dB) Specification
b
0
BER
1/2 Rate
3/4 Rate
-3
10
4.2 dB
5.2 dB
-4
10
4.8 dB
6.0 dB
-5
10
5.5 dB
6.7 dB
-6
10
6.1 dB
7.5 dB
-7
10
6.7 dB
8.2 dB
-8
10
7.2 dB
8.8 dB
/N
required to achieve 10
b
0
7/8 Rate
6.4 dB
7.2 dB
7.9 dB
8.6 dB
9.2 dB
9.9 dB
Specifications
-3
-8
to 10
C–19
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