b. The down-converters are a double conversion type with a 70-MHz output. Frequency selection for the
down-converters is accomplished by front panel controls or by a microprocessor in an associated orderwire
modem in the remote mode. Three down-converters can feed the AJ/CM with a beacon/CCC signal, an
acquisition signal, and a polling signal.
c. The cesium beam standard, which is the principal part of the frequency generation subsystem, is also
redundant. The on-line unit provides outputs of 5 MHz and one pulse per second for precise timing to the
AJ/CM and other units as needed.
d. The transmit subsystem consists of up-converters, amplifiers/mixers, and power amplifiers (PAs).
Redundancy is presented in the PA, high voltage power supply, and amplifier/mixer assemblies. The PA has a
maximum power output of 500 watts with an adjustment range of 20 dB. Three up-converters are provided
with a future development for a fourth. They accept a 70-MHz signal from the orderwire or AJ/CM modem.
Through a conversion process, the transmit frequencies are presented to the intermediate power amplifier (IPA)
/attenuator to be raised to a suitable power level for driving the PA.
4. The AN/FSQ-124 is a component of a DSCSOC which is collocated with a host Earth terminal. The host
Earth terminal can be an AN/GSC-39, an AN/GSC-52, or an AN/FSC-78. The AN/FSQ-124 consists of a
remote orderwire console and four equipment racks that contain up- and down-converters, SAMS, IPAs, and
orderwire modems. The AN/FSQ-124 is operated and maintained by a specially trained operator who is one of
the five individuals normally on shift in the DSCSOC.
LEARNING EVENT 13: ANTIJAMMING AND ECCM TECHNIQUES
1. The AN/MSQ-114, acting as the NCT, has the AJ/CM (ED-1133) that belongs to a family of spread
spectrum modem equipment designed to provide the GMFSC terminals with ECCM capability for operation in
a stressed environment. The spread spectrum link provided by the AJ/CM is more difficult to jam. This signal
can coexist with the FDMA links by sharing the same frequency spectrum and presenting the appearance of not
even being there. This link may well be the last ditch signal available in a stressed environment.
2. The MD-1133 used in the AN/MSQ-114 consists of one chassis assembly, the NCU. The NCU has a
control and bus logic which provides functional terminal modem organization, execution, and control. The
NCU control processor directs external programmable up-/down-converter synthesizer frequency control. The
NCU requires a preset frequency and time reference from an external cesium beam standard. Redundant
frequency standards (HP5061A), which are part of the AN/MSQ-114, provide the required time and frequency
references. The NCU provides buffering for time and frequency reference signals for computational and code
use. Software is modularized to specific terminal operations and functions. Terminal tasks are modularly
executed through
SS0031
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