XC
XC
XC
8602JE
8602JE
8602JE
Optical
Optical
Optical
Receiver
Receiver
Receiver
Manual
Manual
Manual
- 6 -
9. 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 input optical 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 input optical 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 input optical power of the
optical receiver is not high enough,
results in the decrease of C/N.
2. The optical fiber active connector
or adapter of the optical receiver has
been polluted.
3. The RF signal level input the
optical transmitter is too low, make
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. Recover the received optical 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
active connector”.
3. Check the RF signal level input the optical
transmitter and adjust to the required input
range. (When the input channels number less
than 15, should higher than 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 strong interference signal
source; change the optical contact point
location if possible to avoid the influence of
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.
