Comtech EF Data CSAT-5060 - Manual (Page 21)

C-Band Transceiver Revision 1
Introduction MN/CSAT5060.IOM
1-3
1.2 T HEORY OF O PERATION
This chapter contains a general description of the theory of operation for the CSAT
Downconverter and Upconverter sections. The CSAT can be used for SCPC/MCPC,
DAMA, and TDMA, as well as for full transponder HDTV and analog TV applications.
In all models, the downconverter and upconverter local oscillators are independently
synthesized to allow simplex or duplex operation. In order to minimize complexity, they
share a common power supply, an internal high stability 10 MHz reference oscillator, and
the Monitor and Control (M&C) unit.
The Downconverter section operates in the frequency range of 3400 to 4200 MHz, with a
temperature compensated gain of 45 dB. This high level of gain provides an IF output signal
level of +13 dBm at 1 dB of gain compression. This provides the capability to handle longer
modem cable runs, or fan out for splitting networks without requiring additional line amplifiers.
The Upconverter section operates over a frequency range of 5845 to 6425 MHz with a
temperature compensated gain. The RF output level is specified as minimum at 1 dB gain
compression over the operating temperature range.
The phase noise performance of both the Upconverter and Downconverter section exceeds the
Intelsat phase noise mask for IBS and IDR services by 6 dB. This allows phase dependent
demodulators to provide the best possible performance. The close-in phase noise is also very low
making the converter ideal for low data rate applications such as DAMA hub earth stations.
An auto select RS-232 or RS-485 pin out is available in the circular COM connector on the
exterior of the chassis. All configuration control, status retrieval and unit adjustments are
available as ASCII commands through this interface.
Comtech EF Data transceivers are designed to operate continuously at an ambient temperature of
-40°C, with the unit temperature at approximately -25°C.
After power-up at temperatures below -30°C, it may take up to 45 minutes tor the unit
temperature to stabilize. During this time, the transceiver may log various alarms/events. This is
normal and is to be expected.