Comcast LT1550-E, Instruction Manual

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LT1550-E
www.comcast-sa.com
Working principle
LT1550-E series transmitter has 7 function modules: RF control, DFB laser,
optical modulator, SBS control, CSO control, communication/display control
and power supply.
Automatic gain control circuit (AGC) or manual gain control circuit (MGC)
amplifies the RF signal. AGC or MGC control makes the optical modulator
maintain a suitable input level. Use the detected RF root-meansquare(RMS)-
total power to calculate the optical modulation index(OMI).
In general we recommend using the AGC function, and special users can use
the MGC function to adjust the CNR/CSO/CTB performance indexes.
The core of transmitter is the optical modulator. The 1550nm signal input the
optical modulator, make the laser intensity changed follow the external RF
signal voltage, and then generate the AM optical signal.