The working principle of digital video optical transceiver

Optical transceiver is the terminal equipment for optical signal transmission. The improvement of technology and the reduction of the price of optical fiber make it well applied in various fields. Therefore, the manufacturers of various optical transceivers have sprung up like mushrooms after a rain. However, most of the technologies of these manufacturers are not fully mature, and the development of new technologies requires a lot of capital, manpower, and material resources. This results in the fact that most of the manufacturers are small and medium-sized enterprises, and various brands have also appeared. But the quality is still the same. Foreign optical transceivers are good but expensive. Therefore, domestic manufacturers have transformed their production of optical transceivers to meet domestic needs.

In the long-distance optical fiber transmission, the optical cable has little effect on the transmission of optical signals. The transmission quality of the optical fiber transmission system mainly depends on the quality of the optical transceiver, because the optical transceiver is responsible for electrical/optical and optical/electrical conversion, as well as optical emission and optical reception. As a terminal device for transmitting optical signals, optical transceivers are generally used in pairs, divided into optical receivers and optical transmitters. Optical transmitters are used to convert electrical signals into optical signals to achieve electrical/optical conversion, and input optical signals into optical fibers for transmission. The optical receiver is used to restore the optical signal received from the optical fiber to an electrical signal to achieve optical/electrical conversion. Its pros and cons directly affect the entire system, so it is necessary for many new users or interested users to understand the performance and application of the optical transceiver in order to better configure and purchase.

The working principle of digital video optical transceiver

At present, most digital video optical transceivers use 10bit or 8bit quantization coding, and the corresponding sampling frequency is above 13.5Mhz or 16.6Mhz. Use 155Mb/s (single channel video), 622Mb/s (4 channel video), 1.25G b/s (8 channel video) and 2.5G b/s (16 channel video) four rate level optical transmission platform. Optical components generally use transceiver integrated optical modules, which are widely used in telecommunications equipment, with excellent reliability and stability, especially with near-ideal optical dynamic transmission range, which can make transmission equipment within the maximum optical fiber link loss range without adjustment It can work normally. The superiority of the digital signal makes the video signal less affected by distortion and interference in the process of transmission and processing, and the transmission quality greatly exceeds that of the analog optical transceiver. The video image in the digital video optical transceiver must first be digitized, that is, the analog/digital (A/D) conversion is realized through sampling and quantization coding, and then the multi-channel digital video signal or digital audio, data and other signals are converted using high-speed digital multiplexing technology. Multiplexing into a high-speed code stream, and then using a high-speed digital optical transmission platform for transmission. General system performance indicators can reach: weighted signal-to-noise ratio>65dB, excellent ones can be>70dB, differential gain<1%, differential phase<1°, much higher than the weighted signal-to-noise ratio of analog optical transceiver>56dB, excellent ones can>60dB , Differential gain <3%, differential phase <3°. In particular, the indicators of the multi-channel digital video optical transceiver channel have a good consistency, and the mass-produced equipment also has a fairly high consistency.