NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
- 3 -
1.
Overview
1.1
About This Manual
This instruction manual is a complete guide to install and operate the (1RU)
NCM-1550-EM30 series 1550nm externally modulated optical transmitter. Please
read the entire manual before beginning installation.
This manual applies to NCM-1550-EM30 series externally modulated optical
transmitter.
•
Chapter 1 gives general information about the NCM-1550-EM30 series 1550nm
externally modulated optical transmitter.
•
Chapter 2 describes the complete technical specifications of NCM-1550-EM30.
•
Chapter 3 describes the front/rear panel interfaces and menu system.
•
Chapter 4 tells you how to install NCM-1550-EM30 series externally modulated
optical transmitter.
•
Chapter 5 tells you the communication setting of NCM-1550-EM30.
•
Chapter 6 describes maintenance and what to do in the event of problems.
1.2
Product Description
NCM-1550-EM30 series optical transmitter is a 1550nm DFB laser externally
modulated transmitter. It is specially developed for the CATV signal that satisfies
HFC network, and the long-distance transmission of cable phone and cable data.
Working principle
NCM-1550-EM30 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.
