Modems
CDM-Qx & CDM-QxL Multi-Channel
Satellite Modems with
DoubleTalk
®
Carrier-in-Carrier
®
Overview
The CDM-Qx and CDM-QxL Multi-Channel Satellite Modems offer DoubleTalk
®
Carrier-in-Carrier
®
bandwidth compression capability, allowing transmit and receive carriers of a full-duplex satellite link to
share the same transponder space. DoubleTalk Carrier-in-Carrier enables multi-dimensional optimization,
thereby allowing satellite communications users to:
• Reduce operating expenses (OPEX)
• Increase throughput without using additional transponder resources
• Increase availability (margin) without using additional transponder resources
• Reduce capital expenses (CAPEX) by allowing a smaller BUC/HPA and/or antenna
• Or, a combination to meet specific user needs
Features
• DoubleTalk Carrier-in-Carrier bandwidth compression
• Four slot chassis, allowing flexible configuration
• CDM-Qx: 50 to 90, 100 to 180 MHz
CDM-QxL: 950 to 1950 MHz
• Data Rate: 32 kbps to 20 Mbps
• Modulation: BPSK, QPSK, 8PSK and 16-QAM
• Forward Error Correction (FEC): Viterbi, Concatenated Reed Solomon and Turbo Product Coding
(TPC) (IESS-315 Compliant)
• Data Interface: EIA-422, V.35, Sync EIA-232, G.703 T1, G.703 E1, Quad G.703 E1, G.703 E2 and
HSSI
• Enhanced D&I++ for Single & Quad E1
• M&C: EIA-232, EIA-485, and 10/100Base-T Ethernet with SNMP, HTTP and Telnet support
Typical Users
• Satellite Service
Providers
• Fixed Line Operators
• Service Providers
• Government & Military
• Enterprise
• Oil Field Service
Providers
Common Applications
• Cellular Backhaul
• G.703 Trunking
• Offshore & Maritime
Communications
• Embedded Distant-end Monitor and Control (EDMAC)
• Automatic Uplink Power Control (AUPC) Spectrum Analyzer Function
• Asymmetric Loop Timing
• Common frequency reference for all modules
• Individual modulator output power control
• CDM-QxL: 10 MHz reference for BUC, FSK communications and optional BUC power supply
• CDM-QxL: 10 MHz reference and LNB power supply
• Interoperable with many Comtech EF Data satellite modems: CDM-550T, 570, 570L, 600, 600L, SDM-8000, 300A, and 300L3
Turbo Product Coding
The CDM-Qx/QxL offer 2
nd
generation Turbo Product Codec as an option. TPC provides increased coding gain with low decoding delay.
Combined with DoubleTalk Carrier-in-Carrier, they provide unprecedented savings in transponder bandwidth and power utilization as well
as earth station BUC/HPA size.
QUAD E1 Interface (QDI) with Enhanced D&I++
The CDM-Qx/QxL supports a Quad E1 interface that can aggregate up to four synchronous full or fractional E1s into a single carrier, with
very low overhead. This provides significant CAPEX savings by reducing the number of modems and the simultaneous reduction in
BUC/HPA size due to the elimination of multi-carrier backoff.
A proprietary, closed network Drop & Insert (D&I++) allows for Dropping or Inserting any combination of 1 to 31 Time Slots on each E1.
D&I++ is supported for E1-CCS only.
Comments to this Manuals