Comtech EF Data CDM-760 - Manual (Page 41)

Introduction Revision 2
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
1–15
1.3.7 Adaptive Coding and Modulation (ACM)
ACM Operational Mode Functional in DVB-S2 or DVB-S2-EB1/EB2 network specification modes
Symbol Rate Range 1 to 150 Msps
Interface
10/100/100BaseT Ethernet, with auto-sensing 10/100/1000 and auto-crossover detection or optional
Optical Gigabit Ethernet interface
Remote Es/No reporting Automatically reported from remote modem
Max span of data rate 0.1 to 314 Mbps (entire range of modem capability)
Switch point
(decreasing Es/No)
Corresponds to Es/No (plus impairments) at QEF (~PER = 10 -7 )
Max fading rate Configurable Target Es/No margin from 0.0 to 4.5 dB
Max ModCod update rate
Updates to the MODCOD can happen up to 4 times per second (no restriction on distance between
MODCODs)
Configurable parameters
Minimum and Maximum ModCod
Remote Demodulator Unlock options:
• Maintain current ModCod
• Go to minimum ModCod
Es/No Target Margin: 0.0 to 4.5 dB0 in 0.1 dB steps
Modulation Type Impairment selection:
• Impairment for QPSK, 8PSK, 16APSK, 32APSK, and 64APSK: 0 to 9.9 dB in 0.1 dB steps
• Impairment for QPSK ≤ 8PSK ≤ 16APSK ≤ 32APSK≤ 64APSK
Monitored parameters
Tx and Rx ModCods
Local and Remote Es/No: (-3.0 dB to +22.0dB, 0.1dB resolution)
Configuration and monitor menus displaying data rate, modulation and code rate update dynamically
with ModCod
1.3.8 DoubleTalk ® Carrier-in-Carrier ® (CnC)
Operating Mode Requires the two carriers in a duplex circuit to share a common frequency. Different symbol rates are
allowed.
Symbol Rate Range 0.1Msps to 63 Msps
CnC Ratio Ratio of Interferer Carrier Power to Desired Carrier Power (in dB). Positive values represent a stronger
Interferer Carrier, and negative values represent a stronger Desired Carrier. Range is +7 dB to -7 dB.
Symbol Rate Ratio 3:1 Tx/Rx or Rx/Tx
Inbound/Outbound frequency
uncertainty
±100kHz
Delay range 0 - 300 ms (230 - 290 ms factory default)
Es/No Degradation (dB)
measured at 0.0 dB CnC Ratio
QPSK, 0.3 dB
8-PSK, 0.3 dB
16-APSK, 0.4 dB
32-APSK, 0.6 dB
Monitor Functions Delay, in milliseconds
Frequency offset (between outbound interferer and desired inbound): 100 Hz resolution
CnC ratio, in dB (ratio of absolute power, outbound interferer to desired inbound)
CnC Monitor Accuracy ± 1.0 dB for symmetric symbol rate