Comtech EF Data SNM-1010L - Manual (Page 179)

SNM-1010L Data/Control Modem Revision 0
Theory of Operation MN/SNM1010L.OM
Mode
Eb/No at
BER = 10 -6
Guaranteed
(Typical in
parentheses)
Eb/No at
BER = 10 -8
Guaranteed
(Typical in
parentheses)
Spectral
Efficiency
Symbol Rate
Occupied
Bandwidth
for 1 Mbps
Carrier
(see Note 1)
QPSK Rate 1/2 Viterbi
(see Note 1) 6.0 dB
(5.5 dB)
7.3 dB
(6.8 dB)
1.00 bits/Hz 1.0 x bit rate 1190 kHz
BPSK Rate 21/44 Turbo
2.9 dB
(2.6 dB)
3.3 dB
(3.0 dB)
0.48 bits/Hz 2.1 x bit rate 2493 kHz
BPSK Rate 5/16 Turbo
2.4 dB
(2.1 dB)
2.8 dB
(2.5 dB)
0.31 bits/Hz 3.2 x bit rate 3808 kHz
QPSK/OQPSK
Rate 1/2 Turbo
(see Note 3)
3.5 dB
(3.2 dB)
3.6 dB
(3.4 dB)
1.00 bits/Hz 1.0 x bit rate 1190 kHz
QPSK/OQPSK
Rate 3/4 Turbo 3.8 dB
(3.3 dB)
4.4 dB
(4.0 dB)
1.50 bits/Hz 0.67 x bit rate 793 kHz
8PSK Rate 2/3 TCM
and RS (IESS-310)
(see Note 2)
6.5 dB
(6.2 dB)
6.9 dB
(6.6 dB)
1.82 bits/Hz 0.56 x bit rate 666 kHz
8PSK Rate 3/4 Turbo
6.7 dB
(6.3 dB)
7.4 dB
(7.0 dB)
2.25 bits/Hz 0.44 x bit rate 529 kHz
Notes:
1. The occupied bandwidth is defined at the width of the transmitted spectrum taken at the –10 dB
points on the plot of power spectral density. This equates to 1.19 x symbol rate for the modem
transmit filtering.
2. Included for comparative purposes.
3. Future
option.
6–17