Comtech EF Data CLO-10 - Manual (Page 31)

CLO-10 Link Optimizer Revision 1
Introduction MN/CLO-10.IOM
1.5.2 Hardware Options
Redundancy is the only available hardware option for the CLO-10. See Appendix A.
REDUNDANT SYSTEM OPERATION for more information.
If the user wishes to add redundancy to an existing single-thread system, the existing standalone
setup may be converted by purchasing and installing an IOSM interface in place of the original
IOM interface. More specifically, the CLO-10 designated as the system’s Redundant Unit must be
equipped with an IOM, while each CLO-10 within the redundant system designated as a Traffic
Unit will require the IOSM interface.
1.6 Functional Description
1.6.1 What is DoubleTalk™Carrier-in-Carrier
®
?
The CLO-10 utilizes Carrier-in-Carrier
®
(CnC): Comtech EF Data’s implementation of Applied
Signal Technology, Inc.’s patented (United States #6,859,641) DoubleTalk™ signal processing
algorithm technology, which allows both the forward and reverse carriers of a full duplex link to
share the same segment of transponder bandwidth..
CnC allows satellite users to achieve spectral efficiency (i.e., bps/Hz) that cannot be achieved with
traditional links. For example, CnC used with a pair of 16-QAM carriers achieves the bandwidth
efficiency of 256-QAM (8bps/Hz when using uncoded operation as a baseline for both modulation
types) with the power efficiency that is closer to that of 16-QAM. This allows CnC to not only
provide significant operating expenditure (OPEX) savings, but also reduce capital expenditure
(CAPEX) by allowing a smaller BUC/HPA and/or antenna.
A CLO-10 at each end of the link suppresses the uplink carrier (at the near end) and allows the
distant end carrier to be received by the (near end) demodulator. The CLO-10 operates on the
standard IF band of 50-90 MHz and 100-180 MHz and allows users to upgrade existing systems
while preserving their initial investment in modems and up/down converters. By placing the CLO-
10 in the signal path between the modem and the up/down converters, up to 50% savings in
bandwidth can be immediately realized.
Figure 1-4 illustrates a conventional, full duplex satellite link where two carriers are placed in non-
overlapping channels.
Figure 1-5 shows operation of the same link but utilizing the CLO-10 on both ends of the link. The
two carriers now overlap and occupy half the bandwidth of the scenario in Figure 1-4.
The transponder downlinks the composite signal containing both carriers on the same band to the
CLO-10 which then translates the signal to near baseband where it can be filtered (decimated) and
then processed as a complex envelope signal. The CLO-10 next suppresses the version of the near end
carrier on the downlink side and then remodulates the desired carrier to the modem for demodulation.
The CLO-10 operates on the IF signal between the modem and the up/down converters and is
waveform agnostic. This means that no prior knowledge of the underlying modulation, FEC, or any
other waveform specific parameter is required in order to perform the signal suppression operation.
The only caveat to this is that the waveform must be “sufficiently random”.
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