Optical transceiver is the transmission equipment in the optical communication system, mainly for photoelectric conversion and transmission functions. It is generally used for functions such as telecommunications, electric power, monitoring, industrial control, and video transmission, and has a wide range of applications in various industries. The often said optical transceiver refers to the optical transceiver used in the monitoring system to transmit comprehensive information such as video, data, Ethernet, and audio. Mainly divided into analog optical transceiver and digital optical transceiver. Based on the difference of the transmission medium, there are single-mode optical transceivers and multi-mode optical transceivers. Next, Feichang Technology will give you a detailed introduction to the application and common failures of the optical transceiver in the optical communication system. If you are interested, come and learn about it!
The digital optical transceiver digitizes the image, voice, and data signals to be transmitted, and then multiplexes these digital signals to convert multiple low-speed digital signals into one high-speed signal, and convert this signal into an optical signal. At the receiving end, the optical signal is restored into an electrical signal, and the restored high-speed signal is decomposed into the original multiple low-speed signals, and finally these data signals are restored into image, voice and data signals. The analog optical transceiver is to modulate the amplitude or frequency of the signal to be transmitted and then convert the modulated electrical signal into an optical signal. At the receiving end, the optical signal is restored to an electrical signal, and then the signal is demodulated to restore the image, voice or data signal.
Digital optical transceivers have high signal quality, without the shortcomings of severe intermodulation interference during simultaneous transmission of analog FM, phase modulation, and amplitude modulation optical transceivers, easy to be affected by the environment, poor transmission quality, and poor long-term stability. Therefore, digital optical transceivers will gradually Replace the analog optical transceiver.
At present, in the fields of highway, transportation, electronic police, surveillance, security, industrial automation, electric power, customs, water conservancy, banking, etc., optical transceivers such as video image, audio, data, and Ethernet have begun to be widely used.
Application of optical transceiver in security monitoring
The role of optical transceiver in security is mainly to play the role of optical transceiver itself. The function of the optical transceiver is to convert some signals with a relatively short transmission distance into signals with a relatively long transmission distance for transmission. The main function is to increase the transmission distance and play a cost-saving role in monitoring (multi-channel video signals can use one Optical fiber transmission).
The optical transceiver will also have some failures during use. The following are the common failures and solutions of optical transceivers, and see how experts solve them.
No video signal
1. Check whether the power supply of each device is normal.
2. Check whether the video indicator of the corresponding channel at the receiving end is on,
if the indicator is on (the light is on to prove that the channel has video signal output at this time). Then check whether the video cable between the receiving end and the terminal equipment such as the monitor or DVR is well connected, and whether the video interface connection is loose or there is false welding.
The video indicator on the receiving end is off. Check whether the video indicator of the corresponding channel on the front end is on. (It is recommended to re-power on the optical receiver to ensure the synchronization of the video signal)
If the above methods cannot eliminate the fault and there are devices of the same model, you can use the replacement inspection method (requires the equipment to be interchangeable), that is, connect the fiber to another A working receiver at one end or replacing the transmitter at the far end can accurately determine the faulty equipment.
Interference snowflakes appear on the screen.
1. Check whether the pigtail is excessively bent (especially in multi-mode transmission, try to unfold the pigtail and avoid excessive bending).
2. Check whether the connection between the optical port and the flange of the terminal box is reliably connected and whether the flange core is damaged or not.
3. Whether the optical port and pigtail are too dirty, clean them with alcohol and cotton, and then insert them after they are dry.
4. When laying lines, try to use 75-5 cables with good shielding and better transmission quality for video transmission cables, and try to avoid AC lines and other objects that easily cause electromagnetic interference.
There is no control signal or the signal is abnormal.
1. Check the data port definition in the product manual to see if the data cable is connected correctly and firmly. Especially if the positive and negative poles of the control line are connected reversely.
2. Check whether the control data signal format sent by the control equipment (computer, keyboard or DVR, etc.) is consistent with the data format supported by the optical transceiver, and whether the baud rate exceeds the range supported by the optical transceiver (0-100Kbps).
3. Check whether the data cable is connected correctly and firmly according to the data port definition in the product manual. Especially if the positive and negative poles of the control line are connected reversely.
The input signal of a branch disappears.
1. Observe the alarm information of the optical transceiver, and find that the 2/8 multiplexing board in the direction has a red light. At the same time, the I1 light of the monitoring alarm board is on, indicating that the 2M1 branch of the board is faulty.
2. Judge whether it is the failure of the branch unit of the optical transceiver or the failure of the input interface from the program-controlled computer room to the optical transceiver. There are two ways to determine: the first is to self-loop the input port of the branch. If the failure does not disappear, the branch unit is faulty. ; If the fault disappears, it is a fault on the computer room side of the program control. The second type is to use a transmission performance analyzer to monitor online at the branch input port. If "code input is normal", it means the optical transceiver branch unit is faulty; if "code input is interrupted", it is on the computer room side of the program control. For example, use the first method to determine that it is a fault on the program-controlled computer room side.
3. Further on-line test with the transmission analyzer at point B of the digital distribution rack is "code input interruption", indicating that the fault is between the switch unit-the input port of the digital distribution rack.
4. Immediately notify the personnel in the program-controlled computer room to observe the status of the switch. It is found that the relay board to the Qiangbai circuit has an alarm light on, and the board is replaced immediately, the alarm disappears and the circuit is unblocked.
This fault is caused by the switch-related digital relay unit sending no output. This kind of failure often occurs on the joint of the cable between the switch and the optical transceiver. Need to immediately use the spare line to grab the circuit.
Optical receiving failure
1. Observe the alarm information of the
optical transceivers of both parties. Observe the optical transceivers and find that the red and yellow lights of the light board flash alternately, and the lights are on and off; the lights on the monitoring alarm panel I7 and I8 are on. These messages indicate that Dali has received 10-3 and 10-6 codes; observing the Qiang white light repeater, there is no warning information. These indicate that this is a unidirectional optical path failure.
2. There are three methods to determine whether the optical board is faulty or the optical cable fault: a. Replace the two optical boards with a spare board and the fault does not disappear, indicating that the fault is an optical cable fault, otherwise, it is an equipment failure. b. Use an optical power meter to measure the light emitting and receiving power respectively, and it can also be judged whether the optical board or the optical cable is faulty. c. Use pigtail + optical attenuator to send and receive self-loop on the optical board to determine whether the optical board or the optical cable is faulty. I use the first method to determine that the cable is faulty.
3. If the optical cable has a spare core, you can try it; if there is no spare core, you need to carefully judge whether it is a pigtail or an outdoor optical cable? Because a single-core optical cable is not good, and it is not broken at all, the outdoor cable may be broken. If the sex is small, it is better to check the pigtail first.
Well, the above content is the detailed introduction of Feichang Technology on the application of optical transceivers in optical communication systems and the analysis of common failure problems. I hope it can be helpful to you!