Comtech EF Data CDM-600/600L User Manual
Page 50
CDM-600/600L Open Network Satellite Modem
Revision 3
Introduction
MN/CDM600L.IOM
1–22
Monitor Functions
• Eb/No estimate, 2 to 16 dB (± 0.25 dB accuracy)
• Corrected Bit Error Rate, 1E-3 to 1E-10
• Frequency offset, ± 32 kHz range, 100 Hz resolution
• Buffer fill state, in percent
• Rx signal level, in dBm
Clock tracking range
± 100 ppm min
Acquisition range
±1 to ± 32 kHz, programmable in 1kHz increments
Acquisition time
(CDM-600L)
Viterbi QPSK
6db Eb/No with
± 32 kHz frequency Uncertainty
Code Rate
Data Rate
Tacq
P(t
1/2
< 9.6 kbps
< 35 sec
95%
1/2
≥ 9.6 kbps < 64 kbps
< 15 sec
95%
1/2
≥ 64 kbps < 196 kbps
< 2 sec
95%
1/2
≥ 196
< 1 sec
95%
3/4
9.6 kbps
< 25 sec
95%
7/8
9.6 kbps
< 30 sec
95%
Sequential QPSK
6db Eb/No with
± 32 kHz Frequency Uncertainty
Code Rate
Data Rate
Tacq
P(t
1/2
< 9.6 kbps
< 40 sec
95%
1/2
≥ 9.6 kbps < 64 kbps
< 15 sec
95%
1/2
≥ 64 kbps < 196 kbps
< 2 sec
95%
1/2
≥ 196
< 1 sec
95%
3/4
9.6 kbps
< 25 sec
95%
7/8
9.6 kbps
< 30 sec
95%
Turbo
6db Eb/No with
± 32 kHz Frequency Uncertainty
Code Rate/Mod
Data Rate
Tacq
P(t
5/16 BPSK
9.6 kbps
< 6 sec
95%
21/44 BPSK
9.6 kbps
< 15 sec
95%
Acquisition time
(CDM-600)
Highly dependent on data rate, FEC rate, and demodulator acquisition range.
Examples:
200 ms average at 64 kbps, R1/2 QPSK, ±32 kHz acquisition sweep range, 6dB Eb/No
5 s average at 9.6 kbps, R1/2 QPSK, ±10 kHz, 6dB Eb/No
Note
that Reed-Solomon increases acquisition time, due to the additional time taken for the RS
decoder to declare synchronization.
VITERBI
BER performance
(met in the presence of
two adjacent carriers,
each 7 dB higher than
the desired carrier)
For:
Rate 1/2 (B, Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 3/4 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 7/8 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
BER=10
-5
5.4 dB (4.9 dB)
6.8 dB (6.3 dB)
7.7 dB (7.2 dB)
BER=10
-6
6.0 dB (5.5 dB)
7.4 dB (6.9 dB)
8.4 dB (7.9 dB)
BER=10
-7
6.7 dB (6.2 dB)
8.2 dB (7.7 dB)
9.0 dB (8.6 dB)
SEQUENTIAL
@ 64 kbps BER
(met in the presence of
two adjacent carriers,
each 7 dB higher than
the desired carrier)
For:
Rate 1/2 (B, Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 3/4 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 7/8 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
BER=10
-5
4.8 dB (4.2 dB)
5.8 dB (5.3 dB)
7.0 dB (6.6 dB)
BER=10
-6
5.2 dB (4.5 dB)
6.4 dB (5.8 dB)
7.5 dB (7.2 dB)
BER=10
-7
5.6 dB (4.8 dB)
6.9 dB (6.3 dB)
8.0 dB (7.7 dB)
SEQUENTIAL
@ 64 kbps BER
(met in the presence of
two adjacent carriers,
each 7 dB higher than
the desired carrier)
For:
Rate 1/2 (B, Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 3/4 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
Rate 7/8 (Q, OQ)
Guaranteed Eb/No
(typ
value in parentheses):
BER=10
-5
4.8 dB (4.2 dB)
5.8 dB (5.3 dB)
7.0 dB (6.6 dB)
BER=10
-6
5.2 dB (4.5 dB)
6.4 dB (5.8 dB)
7.5 dB (7.2 dB)
BER=10
-7
5.6 dB (4.8 dB)
6.9 dB (6.3 dB)
8.0 dB (7.7 dB)