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CDM-625 Advanced Satellite Modem
Introduction
LDPC CODEC BER
Rate 2/3 8-PSK
Rate 3/4 8-PSK
(With two adjacent
carriers, each 7 dB
higher than the desired
carrier)
LDPC CODEC BER
Rate 2/3 8-QAM
Rate 3/4 8-QAM
(With two adjacent
carriers, each 7 dB
higher than the desired
carrier)
LDPC CODEC BER
Rate 3/4 16-QAM
(With two adjacent
carriers, each 7 dB
higher than the desired
carrier)
Plesiochronous/
Doppler Buffer
Monitor Functions
Rx Carrier Level versus Symbol Rate
IF band (50-180 MHz)
10
0
Maximum
-10
-20
-30
-40
-50
-60
-70
-80
10
100
Symbol Rate in ksps
8-PSK Rate 2/3 LDPC
Guaranteed Eb/No:
(typical value in
For:
parentheses)
-5
BER=10
-9
BER=10
5.7 dB (5.2 dB)
8-QAM Rate 2/3 LDPC
Guaranteed Eb/No:
(typical value in
For:
parentheses)
-5
BER=10
4.6 dB (4.2 dB)
-9
BER=10
5.0 dB (4.6 dB)
16-QAM Rate 3/4 LDPC
Guaranteed Eb/No:
(typical value in
For:
parentheses)
-5
BER=10
6.8 dB (6.2 dB)
-5
BER=10
7.1 dB (6.8 dB)
Selectable size of 64 to 262,144 bits, in 16-bit steps (with added limitations for G.704 frame boundaries)
Size selection is displayed in bytes and milliseconds
Supports asymmetric operation - when buffer is clocked from Tx clock, Rx and Tx rates do not need to
be identical
Eb/No estimate:
2 to 10 dB with ± 0.3 dB accuracy
0 to 16 dB with ± 0.5 dB accuracy
Corrected Bit Error Rate, 1E-3 to 1E-10
Frequency offset, ± 32 kHz range, (or 200 kHz range, depending on band and symbol rate) 100 Hz
resolution
Buffer fill state, in percent
Receive signal level:
950-1950 MHz band accuracy: ± 3 dB
50-180 MHz band accuracy: ± 2 dB
Minimum
1000
10000
8-PSK Rate 3/4 LDPC
Guaranteed Eb/No:
(typical value in
parentheses)
-
5.6 dB (5.2 dB)
6.0 dB (5.6 dB)
8-QAM Rate 3/4 LDPC
Guaranteed Eb/No:
(typical value in
parentheses)
5.6 dB (5.2 dB)
6.0 dB (5.6 dB)
Rx Carrier Level versus Symbol Rate
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
10
100000
1–14
MN-0000036 (Ref MN/CDM625.IOM)
Notes:
1) Rate 21/44 QPSK is shown
as Rate 1/2 on the Front Panel
display, etc.
2) The demod acquisition
and tracking threshold for
OQPSK is approx 1 dB
worse than the QPSK case in
this mode.
L Band (950 - 1950 MHz)
Maximum
Minimum
100
1000
10000
Symbol Rate in ksps
Revision 1
100000
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