Questtel L-RF-2mW-TX Manuale utente
User Manual
CATV 4 mW RF Optical Transmitter
47-750/862/1003 MHz
L-RF-4mW-TX
www.questtel.com [email protected]
1
Foreword
Foreword
This manual applies to 1310nm AM direct modulated optical transmitter with
SNMP network management interface. It mainly describes the performance
characteristics, technical parameters, installation and debugging, common
troubleshooting, and other related content of the product. In order to ensure that the
equipment can be successfully installed and safely operated, please read this manual
carefully before installing and debugging the equipment. And the installation and
debugging should be strictly according to the specified steps on the manual to avoid
unnecessary damage to equipment or accident harm to the operator. Any questions,
please contact with us in time.
Special Tips:
■Optical transmitter is professional equipment, and its installation and debugging
must be operated by special technician. Read this manual carefully before
operating to avoid damage to equipment caused by fault operation or accident
harm to the operator.
■While the optical transmitter is working, there is an invisible laser beam from the
optical output adapter on the front panel. Avoiding permanent harm to the body
and eye, the optical output should not aim at the human body and human should
not look directly at the optical output with the naked eye!
■Please make sure that the ground terminal of the case and power outlet has been
reliably grounding before turning on the power (Grounding resistance should be
less than 4Ω) to prevent the static damage the pump laser device and harm to
human because of case charged.
■To ensure the equipment can work stable over a long time in voltage unsteady or
poor voltage wave region, it´s recommend to the customer that he equips special
AC regulated power supply, or even AC uninterrupted power supply (UPS) system
for conditional regions. In the region with large temperature variation
environment (The equipment's ideal work environment temperature is 25°C) or
bad room environment it´s recommend to the customer that he equips special
air-condition system to improve the work environment.
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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1. Product Summary
1310nm AM direct modulated optical transmitter is the most important equipment to
construct the CATV HFC network. It mainly used for the long distance optical fiber
transmission of TV image signal, digital television signal, telephone voice signal and
data (or compressed data) signal. This product does use the high-performance DFB
laser as the optical source. The RF drive part adopts RF power digital automatic
processing technology and advanced RF pre-distortion circuit, and built-in
microcomputer automatic monitoring system, to ensure the excellent performance
indicators.
2. Performance characteristics
■Adopt high-performance coaxial/butterfly DFB laser, narrow spectral lines, good
linearity and high output power.
■The RF drive part adopts the RF power digital automatic processing technology.
Automatic processing the drive level power according to the RF input signal level
and the number of channels (15-84 channels), make the CSO, CTB and C/N index
always at the optimal value to ensure the overall performance.
■Advanced multi-frequency RF pre-distortion technology, combined with the GaAs
device, effectively improve the CATV system most important CTB and CSO
index, C/N index also gets the maximum upgrade.
■Adopt advanced 32 bit processor; coordinate with perfect automatic monitoring
system circuit. It can timely and accurately monitor working status of the laser to
ensure a stable optical output power and effectively extend the working life of the
laser.
■Built-in blue screen 160×32 dot matrix LCD monitor on the front panel,
accurately showing all working status parameters.
■19″1U standard rack mount, equipped standard IEEE802.3 10Base-T Ethernet
interface and RS232 interface, can expediently realize network management
monitoring.
■Fully support <GB/T 20030-2005 HFC Network device management system
specification>.
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
3
3. Block Diagram
Note: Adopts butterfly DFB laser or coaxial DFB laser.
4. Technology Parameters
4.1 Link test conditions
Special instructions: The performance parameters of this manual according to
the measuring method of GY/T 143-2000 <Specifications and methods of
measurement on AM optical transmitter and receiver used in CATV systems>, and
tested under the specified test conditions.
Test condition: With standard optical fiber and standard optical receiver
composed the test link. Set 84 PAL-D analog TV channel signal at 750MHz frequency
range under the specified link loss. When the optical input power of optical receiver is
-1dBm, measure the C/CTB, C/CSO and C/N.
4.2 Technique Parameters Table
Item
Unit
Technique parameters
Optical output power
mW
4
6
8
10
12
14
16
18
20
22
24
26
Optical link loss
dB
7
9
10
11
11.8
12.5
13
13.6
14
14.4
14.8
15.1
Optical wavelength
Nm
1310±20
Laser type
DFB laser
Optical modulation
mode
Direct optical intensity modulation
Optical connector
type
FC/APC or SC/APC
Frequency range
MHz
47-750/862/1003
RF input level
dBµV
72-88
Flatness in band
dB
±0.75
RF input impedance
Ω
75
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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Input return loss
dB
≥ 16（47-550MHz）； ≥ 14（550-750/862/1003MHz）
C/CSO
dB
≥ 60
C/CTB
dB
≥ 65
C/N
dB
≥ 51
AGC control range
dB
±5
MGC control range
dB
0-10
Power supply voltage
V
AC 110V-250V（50Hz）
Consumption
W
30
Operating
temperature
°C
0 -- 45
Storage temperature
°C
-20 -- +65
Relative humidity
%
Max 95% no condensation
Dimension
mm
483（L）×380（W）×44（H）
4.3 Optical link carrier to noise ratio degradation table
Optical
power
Optical link loss (dB)
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
4mW
53.8
52.8
51.8
51
50.1
49.2
48.2
6mW
53.0
52.0
51.0
50.1
49.1
48.1
8mW
52.8
51.9
51.0
50.1
49.2
48.2
10mW
52.9
51.9
51.0
50.1
49.1
48.2
12mW
52.7
51.8
50.8
49.9
49.0
48.0
14mW
52.4
51.5
50.5
49.5
48.6
47.8
16mW
52.0
51.0
50.1
49.1
48.1
18mW
52.5
51.6
50.6
49.7
48.7
47.9
20mW
51.9
51.0
50.0
49.0
48.0
22mW
52.2
51.4
50.4
49.4
48.6
47.8
24mW
51.5
50.3
49.2
48.5
47.7
26mW
51.5
50.2
49.2
48.5
47.6
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
5
5. External Function Description
5.1 Front Panel Description
Schematic diagram of the front panel
1) Power indicator: The light is on while the switching power supply inside is
working.
2) Device running indicator: This indicator will flash after the device start running.
3) Laser working status indicator: Red light means the laser is not working, but the
machine parameters are normal; flashing red light means the machine has broken
down, related fault reason see the alarm menu of the display menu; green light
means the laser is working normal.
4) RF status indicator: Flashing red light means the RF input signal is warned; green
light means RF input signal is normal.
5) 160×32 dot-matrix LCD screen: used to display all the parameters of the machine.
6) Display the exit or cancel key of the setup menu.
7) Display the up or increase key of the setup menu.
8) Display the down or decrease key of the setup menu.
9) Display the enter key of the setup menu.
10) Laser switching key: used to control the working status of laser. “ON” means the
laser is open and “OFF” means the laser is closed. Ensure the key is on “OFF”
position before power on. After passing self-test, rotate the key to “ON” position
according to the displayed message.
11) RF input signal test port: -20dB test port of the rear panel RF input port.
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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5.2 Rear Panel Description
Schematic diagram of the rear panel
1) RF signal input.
2) RS232 interface (Console): Used for configuring the network management
parameters.
3) LAN interface: correspond with IEEE802.3 10Base-T, used for network
management.
4) Optical signal output: This interface is the optical signal output port of the device.
The connector type is FC/APC. There is an invisible laser beam from this port
while working normal. So the port should not be aligned to human body or naked
eye to avoid accidental injury.
5) Power input 1(Reserved port, configured dual power or not is decided by the
user).
6) Power input 2.
7) Ground stud of the chassis: used for the connection of the device and ground
wire.
8) Fan outlet.
1
2
3
4
5
6
7
8
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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5.3 Displayed Parameter description
1) Power on, if the key is on the off position, shows:
Product’s Logo and model
2) Turn the key to the on position, shows the turn on delay:
Delay countdown
3) After entering the system:
RF input signal level and optical output power
at present
4) Press “Enter” key into the menu index
1. Parameter menu; 2. Set parameters; 3.Alarm menu
5) Sub-menu of parameters
Press “Enter” key into the menu
Content
Meaning
Optical output power of the laser at
present
Bias current of the laser at present
Internal temperature of the laser
Operating current of the laser
thermoelectric cooler
Transmission channel number of the
system
Laser RF signal level at present
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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RF control mode at present
The offset of control level in the AGC
mode
The attenuation of electrically
controlled attenuator in the MGC
mode
Switching power supply output +5V
supply voltage
Switching power supply output -5V
supply voltage
Switching power supply output +24V
supply voltage
Serial number
Internal temperature at present
IP address
Subnet Mask
Gateway
MAC address
Software system version
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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6) Setting menu
Press “Enter” key into the menu
Content
Meaning
Set the displayed optical power unit
Turn on or off the buzzer alarm
Set the control mode of the RF
signal: AGC or MGC
Set the attenuation of MGC
Set the offset of AGC start control
level
Set system transmission channels
number. This parameter is used to
correct the accuracy of displayed
laser RF signal level
Set IP address
Set subnet mask
Set gateway
7) Warning menu
Press “ENTER” into the alarm menu
Optical Transmitter User Manual
L-RF-4mW-TX
www.questtel.com [email protected]
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