LuxGlo TNHFC User manual

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TN NH HF FC C O Op pt ti ic ca al l R Re ec ce ei iv ve er r
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Op pe er ra at ti io on n a an nd d M Ma ai in nt te en na an nc ce e M Ma an nu ua al l

TNHFC
Ver:1220AP
1. Product Summary
TNHFC optical receiver is the bidirectional equipment that is specially developed for HFC
structure bidirectional metropolitan area broadband network. Rely on several years’ research
experience for CATV HFC fiber transmitting equipment. Take full account of the FTTH (Fiber to
the Home) network topology, the engineering technology problem of CATV bidirectional return
channel noise collection and the high reliability network security transmission requirements of
modern CATV business. The return path adopts the burst mode (open the laser when have return
signal), which greatly reduced the noise collection.
2. Performance Characteristics
■Laser control circuit adopts unique design, the work is reliable and stable.
■Excellent AGC characteristic, when the input optical power range is -7～+2dBm, the output
level remains unchanged, CTB and CSO basically unchanged.
■Optimizing circuit design, SMT production process, optimizing the whole signal path, makes
the photoelectronic signal transmission more stable, RF linear indicators higher.
■Professional RF attenuator circuit, with good attenuation linear and high precision.
■GaAs amplifier device, with good index, low distortion and high reliability.
■The return path control adopts burst mode, which greatly reduced the noise collection.
■The shell adopts aluminum die casting, cooling effect is good and the appearance is exquisite.

TNHFC
Ver:1220AP
3. Technique Parameters
3.1 Link testing conditions
The performance parameters of this manual according to the measuring method of GY/T 194-2003
< Specifications and methods of measurement on optical node used in CATV systems >, and tested
in the following conditions.
Test condition:
1. Forward optical receive part: with 10km standard optical fiber, passive optical attenuator and
standard optical transmitter composed the testing link. Set 59 PAL-D analog TV channel signal at
range of 47/85MHz ～550MHz under the specified link loss. Transmit digital modulation signal at
range of 550MHz ～862/1003MHz, the digital modulation signal level (in 8 MHz bandwidth) is
10dB lower than analog signal carrier level. When the input optical power of optical receiver is
-1dBm, the RF output level is 92dBμV, measure the C/CTB, C/CSO and C/N.
2. Backward optical transmit part: Link flatness and NPR dynamic range are the link indexes
which is composed of backward optical transmitter and backward optical receiver.
Note: When the rated output level is the system full configuration and the receiving optical power is
-2dBm, equipment meets the maximum output level of link index. When the system configuration
reduce (that is, actual transmission channels reduce), the output level of equipment will be increased.

TNHFC
Ver:1220AP
3.2 Technique Parameters
Item
Unit
Technique Parameters
THHFC
Forward Optical Receive Part
Optical Parameters
Receiving Optical Power
dBm
-7 ~ +2
Suggested Use Range
dBm
-3 ~ +1
Optical Return Loss
dB
> 45
Optical Receiving Wavelength
nm
1100 ~ 1600
Optical Connector Type
FC/APC, SC/APC (or specified by the user)
Optical Fiber Type
Single mode
Link Performance
C/N
dB
≥ 51 received optical power (-1dBm)
C/CTB
dB
≥ 63
C/CSO
dB
≥ 60
RF Parameters
Frequency Range
MHz
47/54/70/85～862(1003)
Flatness in Band
dB
±0.75
Rated Output Level
dBμV
≥ 92
Max Output Level
dBμV
≥ 92
Output Return Loss
dB
≥16
Output Impedance
Ω
75
Reverse Optical Transmit Part
Optical Parameters
Optical Transmit Wavelength
nm
1310±10, 1550±10 or specified by the user
Laser Type
DFB or FP laser
Optical Output Power
mW
0.5, 1, 2
Optical Connector Type
SC/APC (or specified by the user)
RF Parameters
Frequency Range
MHz
5 ~30/42/55/65, (or specified by the user)
Flatness in Band
dB
±0.75
Input Level
dBμV
75～85 (Suggested input 80)
Input Return Loss
dB
≥ 16
Output Impedance
Ω
75
NPR dynamic range
dB
≥15 (NPR≥30 dB)
Use DFB laser
≥10 (NPR≥30 dB)
Use FP laser
General Performance
Power Voltage
V
DC12V
Operating Temperature
°C
－30～＋70
Storage Temperature
°C
－30～＋70
Relative Humidity
％
Max 95% no condensation
Consumption
W
≤6
Dimension
mm
154（L）╳116（W）╳26（H）

TNHFC
Ver:1220AP
4. Block Diagram
TNHF Cortical node block diagram:
TNHFC block diagram
5. Structure Diagram
1. Return path input test port
2. Forward path input test port
3. RF signal output, DC12V input,
return path input
4. Grounding
5. Received optical power test point
6. Laser operating status indicator
7. Input optical power indicator*
8. Power Indicator
9. Input optical signal
(Input/output port when WDM)
10. Output optical signal
(without this port when WDM)
11. DC12V input
*Note: Optical power＞+2dBm——Red; +2dBm~-8 dBm;-8 dBm~ -15 dBm——Bright orange; ＜-15 dBm——OFF.

TNHFC
Ver:1220AP
6. Common Failure Analysis and Troubleshooting
Failure phenomenon
Failure cause
Solution
After connecting the
network, the image of
the optical contact point
has obvious netlike
curve or large particles
highlights but the image
background is clean.
1. The optical input power of the
optical receiver is too high, make
the output level of the optical
receiver module too high and RF
signal index deteriorate.
2. The RF signal (input the
optical transmitter) index is poor.
1. Check the optical input power and make
appropriate adjustments to make it in the specified
range; or adjust the attenuation of optical receiver
to reduce the output level and improve index.
2. Check the front-end machine room optical
transmitter RF signal index and make appropriate
adjustments.
After connecting the
network, the image of
the optical contact point
has obvious noises.
1. The optical input power of the
optical receiver is not high
enough, results in the decrease of
C/N.
2. The optical fiber connector or
adapter of the optical receiver has
been polluted.
3. The RF input signal level of
the optical transmitter is too low,
make the modulation degree of
the laser is not enough.
4. The C/N index of system link
signal is too low.
1. Check the received optical power of the optical
contact point and make appropriate adjustments to
make it in the specified range.
2. Improve the optical received power of the optical
contact point by cleaning the optical fiber
connector or adapter etc methods. Specific
operation methods see “Clean and maintenance
method of the optical fiber connector”.
3. Check the RF input signal level of the optical
transmitter and adjust to the required input range.
(When the input channels number less than 15,
should be higher than the nominal value.)
4. Use a spectrum analyzer to check the system link
C/N and make appropriate adjustments. Make sure
the system link signal C/N﹥51dB.
After connecting the
network, the images of
several optical contact
points randomly appear
obvious noises or bright
traces.
The optical contact point has
open circuit signal interference or
strong interference signal
intrusion.
1. Check if there is a strong interference signal
source; change the optical contact point location if
possible, to avoid the influence of the strong
interference signal source.
2. Check the cable lines of the optical contact point,
if there is shielding net or situation that the RF
connector shielding effect is not good.
3. Tightly closed the equipment enclosure to ensure
the shielding effect; if possible, add shielding cover
to the optical contact point and reliable grounding.
After connecting the
network, the images of
several optical contact
points appear one or two
horizontal bright traces.
Power supply AC ripple
interference because of the bad
earth of equipment or power
supply.
Check grounding situation of the equipment, make
sure that every equipment in the line has been
reliably grounding and the grounding resistance
must be﹤4Ω.
After connecting the
network, the received
optical power of the
optical contact point is
unstable and changes
continuously. The
output RF signal is also
unstable. But the
detected optical output
power of the optical
transmitter is normal.
The optical fiber connector types
do not match, maybe the APC
type connect to PC type.
The optical fiber connector or
adapter may be polluted
seriously, or the adapter has been
damaged.
1. Check the type of optical fiber connector and
adopt the APC type optical fiber connector to
ensure the normal transmission of optical signal.
2. Clean the polluted optical fiber connector or
adapter. Specific operation methods see “Clean and
maintenance method of the optical fiber
connector”.
3. Replace the damaged adapter.

TNHFC
Ver:1220AP
7. Clean and maintenance method of the optical fiber active connector
In many times, we consider the decline of the optical power as the equipment faults, but
actually it may be caused by that the optical fiber connector was polluted by dust or dirt. Inspect the
fiber connector, component, or bulkhead with a fiberscope. If the connector is dirty, clean it with a
cleaning technique following these steps:
1. Turn off the device power supply and carefully pull off the optical fiber connector from the
adapter.
2. Wash carefully with good quality lens wiping paper and medical absorbent alcohol cotton. If
use the medical absorbent alcohol cotton, still need to wait 1~2 minutes after wash, let the
connector surface dry in the air.
3. Cleaned optical connector should be connected to optical power meter to measure optical
output power to affirm whether it has been cleaned up.
4. When connect the cleaned optical connector back to adapter, should notice to make force
appropriate to avoid china tube in the adapter crack.
5. If the optical output power is not normal after cleaning, should pull off the adapter and clean
the other connector. If the optical power still low after cleaning, the adapter may be polluted,
clean it. (Note: Be carefully when pull off the adapter to avoid hurting inside fiber.)
6. Use compressed air or degrease alcohol cotton to wash the adapter carefully. When use
compressed air, the muzzle aims at china tube of the adapter, clean the china tube with
compressed air. When use degrease alcohol cotton, insert directions need be consistent,
otherwise can’t reach a good clean effect.