Comtech EF Data CDM-600/600L - Manual (Page 49)

CDM-600/600L Open Network Satellite Modem Revision 3
Introduction MN/CDM600L.IOM
1–21
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50
CDM-600 Modulator
typically < -50 dB, and
guaranteed to be
< -45 dB at offsets
> 0.75 Rs
Comtech EF Data
CDM-600 Transmit
Power Spectral Density,
referred to symbol rate
Symbol Rate, R s
Spectral
density,
dB
Intelsat
IESS 308/309
Limit
Intelsat
IESS 308/309
Limit
1.5.2 Demodulator
NOTE: Data Rate Range, Operating modes, Descrambling, Input impedance/return loss etc., as per
Modulator.
Input power range CDM-600L: -130 + 10log(symbol rate) (desired carrier) to –130 + 10 log(symbol rate) + 50 dBm
CDM-600: -30 to -60 dBm (desired carrier)
+35 dBC maximum composite, up to -5 dBm
FEC Viterbi: 3 bit soft decision
Sequential: 2 bit soft decision
Trellis: Per IESS-310
Reed-Solomon(Open Network): Per IESS-308/-309/-310
Reed-Solomon(Closed Network): Proprietary
Turbo Product Codec: 6 bit soft decision, proprietary
LDPC: 5 bit soft decision, proprietary
Plesiochronous/
Doppler Buffer • 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
Comtech EF Data
CDM-600/600L Transmit
Power Spectral Density,
referred to symbol rate
CDM-600/600L
Modulator typically
≤50 dB, and
guaranteed to be
≤45 dB at offsets
>0.75 Rs