Mgc Modes - Motorola GX2 EA1000C Series User Manual

Operation
CW/Video
CW is a secondary mode that uses unmodulated channels for a proof-of-performance
rating. Video is also a secondary mode that is used when modulated channels are
applied to the input of the GX2-EA1000C*/*. CW and Video are used in conjunction with
Preset and Set. When in Set or Preset, you can toggle between CW and Video using the
backplane communication interface. CW and Video are not applicable in Manual mode.
When switching from CW to Video, the RF level decreases by the amount of offset
selected—2 dB, 3 dB, 4 dB, or 5 dB. You can select the offset value using the SDU, the
network management system, or the local access port. This decrease in RF level is
provided to compensate for the difference in average power between CW channels and
modulated video channels.
On initial power up, the factory default mode for the GX2-EA1000C*/* is Preset/Video
mode with a Video mode offset of 4 dB from CW.

MGC Modes

The following settings (submodes) are available in MGC:
Manual
Manual is a primary mode setting that enables you to adjust the RF level in 0.5 dB steps
through the backplane communication interface. Because the gain of the GX2-
EA1000C*/* is not adjusted by the microprocessor after you set the RF level, this mode
is referred to as the "fixed-gain mode". When you select Manual, the previously stored
Manual mode RF attenuator setting is recalled from NVM.
Manual is most useful if the input load is fixed and you prefer to control the RF drive
level to the laser to achieve a certain performance. Reducing the RF attenuation level
from the optimum setting may result in improved CNR, but degrades second and third
order distortion products depending on the channel load. Conversely, increasing the RF
attenuation level from the optimum setting may result in degraded CNR, but slightly
improves second and third order distortion products depending on the channel load.
When you use Manual mode, you must adjust the RF attenuator setting to meet your
specific performance requirements.
Manual Equate
Manual Equate is a primary submode that equates the RF attenuator setting to the
previously selected (Preset, Set, or Manual) RF attenuator setting. You can select
Manual Equate from any mode. As this is a momentary submode, after the RF
parameters are configured by the microprocessor, the GX2-EA1000C*/* is automatically
switched to Manual. You can now make RF level adjustments, as described previously in
"Manual." When you select Manual Equate, the RF attenuator value, previously stored in
Manual mode, is overwritten.
Manual Equate is useful in resetting the Manual mode operating point to a known level.
Its most common use is to equate the Preset mode RF attenuator setting to Manual
mode.
GX2 EA1000C*/* Multi-Wavelength DWDM 1550 nm Laser Transmitter • User Guide
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