NCM NCM-1550-EM30 User manual

NCM-1550-EM30 (1550nm Externally
Modulated Optical Transmitter)
Operating Manual

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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Table of Contents
Table of Contents...................................................................................................... - 1-
Safety Instruction......................................................................................................- 2 -
1. Overview............................................................................................................... - 3 -
1.1 About This Manual ......................................................................................- 3 -
1.2 Product Description ..................................................................................... - 3-
1.3 Product Applications....................................................................................- 4 -
2. Technique Parameters ........................................................................................... - 5-
2.1 Optical Parameters.......................................................................................- 5 -
2.2 Model Test Indicators................................................................................... - 5-
2.3 Test Condition..............................................................................................- 6 -
2.4 Technical Data Sheet.................................................................................... - 6 -
3. Panel Interface and Menu System Description.....................................................- 7 -
3.1 Front Panel...................................................................................................- 7 -
3.1.1 Indicator Description ......................................................................... - 7-
3.2 Rear Panel....................................................................................................- 8 -
3.3 Power Module.............................................................................................. - 8 -
3.3.1 220V Power Module..........................................................................- 8 -
3.3.2 48V Power Module............................................................................- 9 -
3.4 Menu Operation ...........................................................................................- 9 -
3.4.1 Main Menu......................................................................................... - 9 -
3.4.2 Display Menu................................................................................... - 10 -
3.4.3 Set Menu .......................................................................................... - 11-
3.4.4Alarm Menu.....................................................................................- 12 -
3.4.5AGC Mode.......................................................................................- 12 -
3.4.6 MGC Mode......................................................................................- 12 -
3.4.7 FrequencyAdjust ITU in DWDM ...................................................- 13 -
3.4.8 SBS Suppression Adjustment ..........................................................- 13 -
4. Installing the NCM-1550-EM30 Optical Transmitter............................................-
14 - 4.1 Receiving and Inspecting...........................................................................-
14 -
4.2 Precautions.................................................................................................- 14 -
4.3 Mounting NCM-1550-EM30........................................................................- 15 -
4.3.1 Mounting the EM30 in the Rack...................................................... - 15-
4.3.2 Connecting the RF Cables ............................................................... - 15-
4.3.3 Connecting the Optical Fiber Cables...............................................- 15 -
4.3.4 Connecting the Ethernet Cable ........................................................ - 16-
4.3.5 Connecting Power............................................................................- 16 -
5. Communication Setup......................................................................................... - 17-
5.1 RS232 Communication Interface Description...........................................- 17 -
5.2 Set up the Hyper Terminal.........................................................................- 17 -
5.3 Operating Parameters Configuration .........................................................- 19 -
5.4 Remote Monitoring: SNMP....................................................................... - 22 -

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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5.5 WEB Network Management...................................................................... - 23-
6. Maintenance and Troubleshooting...................................................................... - 25-
6.1 Cleaning Fiber Optic Connectors............................................................... - 25-
6.1.1 Cleaning Patch Cord or Pigtail Fiber Optical Connectors ............... - 25 -
6.2 Troubleshooting ......................................................................................... - 26 -
6.3 After-sales Service Description..................................................................- 27 -
6.4 Disclaimer..................................................................................................- 27 -
Safety Instruction

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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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.

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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Stimulated Brillouin Scattering (SBS) occurs, when the optical input power is
greater than a certain threshold value. SBS generate the lower frequency
backscattered light which will attenuate the transmission light and return to the laser
while destroying its performance. Causing optical power fluctuation, generates large
noise, and seriously deteriorates the system carrier to noise ratio (CNR). To improve
the SBS threshold, NCM-1550-EM30 series optical transmitter adopts SBS control
technology which is independent researched and developed by ourselves. The
threshold value can be set up to 19dBm.
The optical modulator has a two-way optical signal output. Parts of that signal
are routed to an InGaAs photodiode. This detection of the optical signal has two
functions:
1) Detect whether the laser is normal working. Once the output optical power is
2dB lower than standard power, alarm will be set off.
2) Detect CSO distortion to optimize the bias point of the optical modulator. For
working normal the detector circuit needs at least two carrier signal inputs with an
interval of 24MHz. There is a CSO initialization program in the boot process. If the
CSO install failed, the RF indicator will flash red, see details in 6.2Troubleshooting.
Block Diagram
1.3 Product Applications
•High-performance long-distance transmission
•High-power distribution network
•Redundancy loop architecture
•FTTx network
•RFOG application
•DWDM network

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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2. Technique Parameters
2.1 Optical Parameters
Item
Unit
Value
Optical Wavelength
nm
1545～1560 (or specified by the user)
Side-mode Suppression ratio
dB
>30
Relative Intensity Noise
dB/Hz
<-160
Wavelength Adjustment
Range
GHz
+/-50GHz
Optical Power
dBm
2*7, 2*8, 2*9, 2*10
SBS Threshold Value
dBm
+13～+19 (Continuously adjustable)
Laser Linewidth
MHz
0.3
2.2 Model Test Indicators
Test Model
C42
D59
D84
D84
Channel Plan
CENELEC42
PAL D59
PAL D84
PAL D
Channel Number
TV/FM/QAM64
42/0/0
59/0/0
84/0/0
30/0/48
Bandwidth Noise
5
5
5
5
CNR Tx/Rx
55.5
54.0
52.5
54.5
CNR Link 1
55.0
53.5
52.0
54.0
CNR Link 2
53.0
52.5
50.5
52.5
CNR Link 3
50.5
50.5
49.0
51.0
CSO Tx/Rx and Link 1
64
65
65
70
CSO Link 2
63
65
65
70
CSO Link 3
62
64
63
65
CTB
65
65
65
68

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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2.3 Test Condition
First stage
EDFA
First
paragraph
fiber length
Second
stage
EDFA
Second
paragraph
fiber length
RX
SBS
(dBm)
Tx/Rx
No
No
No
no
0dBm
13.5
Link 1
No
35km
no
no
0dBm
13.5
Link 2
16dBm
65km
no
no
0dBm
16
Link 3
13dBm
50km
13dBm
50km
0dBm
13.5
Rx with 8 pA/ÖHz input noise current density; EDFA with 5dB noise figure; RF input level at 80
dBμV / TV channel;
2.4 Technical Data Sheet
Item
Unit
Technical Parameters
RF range
MHz
47～1003
RF flatness
dB
+/-0.75
RF return loss
dB
>16
RF input impedance
Ω
75
RF input connector type
F type
Rated input level
dBµV
80
Input level range
dBµV
78~96 (AGC mode, modulating signal)
AGC control range
dB
+3～-3
MGC adjustable range
dB
0~15
Optical connector
SC/APC, FC/APC
Operating temperature
°C
-5～45
Storage temperature
°C
-30～+70
Power Source
Specification
V
90～265VAC
36～72VDC
Consumption
W
≤60
Dimension
mm
483(L) × 455(W) × 44(H)
Total Weight
kg
5.5

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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3. Panel Interface and Menu System Description
3.1 Front Panel
1
Power indicator
2
AGC indicator
3
RF modulation degree
indicator
4
Laser indicator
5
LCD
6
ESC key
7
UP key
8
DOWN key
9
Enter key
10
-20dB RF input test port
11
RF input port (or on the
rear panel, optional)
12
Optical output interface A (or
on the rear panel, optional)
13
Optical output interface B (or
on the rear panel, optional)
3.1.1 Indicator Description
Power indicator
One power supply
LED yellow
Two power supplies
LED green
AGC indicator
AGC mode
LED green
MGC mode
LED off
RF modulation degree
indicator
Normal
LED green
Abnormal
LED flash red
Laser indicator
Bias current, cooling current and
output power are all normal
LED green
At least one of bias current,
cooling current and output power
is abnormal
LED flash red

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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3.2 Rear Panel
1
Ground stud
2
Power module
3
Fan
4
RF input port (or on the front
panel, optional)
5
RS232 interface
6
LAN interface
7
Optical output interface A (or
on the front panel, optional)
8
Optical output interface B (or
on the front panel, optional)
3.3 Power Module
3.3.1 220V Power Module
1
Mounting screws
2
220V power outlet
3
Fuse
4
Power switch

NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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3.3.2 48V Power Module
1
Mounting screws
2
+ Positive terminal block
3
- Negative terminal block
3.4 Menu Operation
3.4.1 Main Menu
Displayed parameters
Comments
Boot display
1.Disp Parameters
Menu one: Display parameters
2.Set Parameters
Menu two: Set parameters
3.Alarm Status
Menu three: Alarm status