CDM-Qx and CDM-QxL are also the first satellite modems to offer DoubleTalk™ Carrier-in-Carrier® bandwidth compression capability that allows the transmit and receive carriers of a full-duplex satellite link to be transmitted in the same transponder space, thereby providing a significant savings in leased bandwidth.
CDM-Qx and CDM-QxL with DoubleTalk Carrier-in-Carrier address common challenges encountered in satellite communications, including:
Figure 1 Without Doubletalk Carrier-in-Carrier
Figure 2 With Doubletalk Carrier-in-Carrier
Carrier-in-Carrier® is based on Applied Signal Technology's DoubleTalk™ bandwidth compression technology. DoubleTalk uses "Adaptive Cancellation", a patented technology that allows the transmit and receive carriers of a full-duplex satellite link to be transmitted in the same transponder space.
Available as an option, DoubleTalk Carrier-in-Carrier, when combined with advanced forward error correction and modulation techniques, can deliver unprecedented operating expense savings.
In addition to OPEX savings, DoubleTalk Carrier-in-Carrier can also provide CAPEX savings by allowing a smaller BUC/HPA and/or antenna.
Figure 1 shows the typical full-duplex satellite link, where the two carriers are adjacent to each other. Figure 2 shows the typical DoubleTalk Carrier-in-Carrier operation, where the two carriers are overlapping, thus sharing the same spectrum.
When observed over a spectrum analyzer, only the Composite is visible. Carrier 1 and Carrier 2 are shown in Figure 2 for reference only
The CDM-Qx and CDM-QxL support Comtech EF Data's proprietary closed network Drop & Insert (D&I++) for E1-CCS. The "n"x64 operation allows any value of "n" up to 31, and permits the simultaneous use of EDMAC and AUPC with minimal overhead. The D&I++ is interoperable with CDM-600/600L for "n" up to 24 (Viterbi and TPC FEC only).
EDMAC & AUPC
The CDM-Qx and CDM-QxL support EDMAC, EDMAC-2, and AUPC. EDMAC/AUPC is compatible with CDM-600/600L and CDM-570/570L. EDMAC-2/AUPC is compatible with CDM-570/570L.
Turbo Product Coding
The CDM-Qx and CDM-QxL offer 2nd generation Turbo Product Codec (TPC) as an option. TPC provides increased coding gain while reducing the decoding delay, thereby leading to significant bandwidth savings. Following code rates are supported:
Monitoring & Control
The CDM-Qx and CDM-QxL provide a range of options for local and remote management. The modem can be managed via the front panel, or the remote M&C port (EIA-232/EIA-485), or the 10/100BaseT Ethernet port. With support for SNMP, http and telnet, the modems can be easily integrated into an IP based management system.
Enhancing the capability of CDM-Qx and CDM-QxL in the field is easy. Features that do not require additional hardware can be added on site, using FAST access codes purchased from Comtech EF Data. The FAST access codes can be entered from the modem front panel.
The CDM-Qx and CDM-QxL support a range of data interfaces - EIA-422, V.35, Sync EIA 232, and G.703 (T1/E1).
CDM-Qx Shown With:
Slot 1 - Modulator Card with G.703 Balanced Interface
Slot 2 - Modulator Card with G.703 Balanced Interface
Slot 3 - Modulator Card with EIA-530 Interface
Slot 4 - Modulator Card with EIA-530 Interface