Figure 1
5
P939
x
A-OTX
Soft Front Panel (SFP)
Status indicates the internal diagnostics for the module. Under the Utilities tab, a
Self-Test can be run to diagnose module issues. Status will indicate "Good" if no
problems are found.
If the Status indicates "Failure," run the Self-Test to check on Module internal
diagnosis.
Bias is the modulator dependent set point bias voltage. Bias will be "Locked" once
the set point is established.
The optical transmitter circuit has a modulator bias voltage controller that selects
the optimum operating quadrature point. The quadrature point establishes the
modulation format. For the P939xA, the analog modulation format is chosen.
Environmental and internal temperature changes can cause the quadrature point to
drift over time.
Initially when the P939xA optical transmitter is turned on, the instrument goes
through a temperature stabilization and self-calibration before the quadrature point
is recognized. This can take up to ten minutes. The laser LED will be RED during this
period. Once the unit has stabilized you may notice the LED blinks between RED
and GREEN. When the LED maintains GREEN, the unit is now locked on to the
P939xA-OTX
Soft Front Panel (Optical Transmitter Module)
Keysight P939xA Streamline Customs User's Guide
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