Comtech EF Data SDM-100A - Manual (Page 23)

SDM-100A Satellite Modem Introduction
Rev. 0 1–7
1.5 BER Performance
The bit energy-to-noise ratio (E
b
/N
0
) required to achieve 10 -5 to 10 -7 bit error rates is listed
in Table 1-2.
Table 1-2. BER Performance Specification
Viterbi K = 7
BER 1/2 Rate 3/4 Rate 7/8 Rate
10 -5 5.5 dB 6.8 dB 8.1 dB
10 -7 6.7 dB 8.3 dB 9.4 dB
The Bit Error Rate (BER) performance of the modem with a Viterbi decoder is shown in
Figure 1-4.
The BER performance of the modem with a sequential decoder is shown in Figure 1-5.
A typical output spectrum of the modem is shown in Figure 1-6.
Notes:
1. The modem alone, without coding, provides operation within 0.5 dB of
theoretical for BPSK, and within 0.8 dB for QPSK, for BERs in the range 10 -1 to
10 -6 .
2. Performance measurements are made with Transmit and Receive IF connected
back-to-back through an additive white Gaussian noise channel.
3. The BER performance is in accordance with IESS-308 specifications.