Radio frequency optical fiber transmission optical workstation for two-way network transformation of cable television

Abstract

The invention relates to a radio frequency optical fiber transmission optical workstation for two-way network transformation of a cable television, which belongs to the field of the cable televisions. The radio frequency optical fiber transmission optical workstation comprises a wavelength division multiplexer, an optical module, a downlink signal optical automatic gain control circuit, a downlink signal amplification circuit, an uplink signal amplification circuit, a radio frequency switching control circuit, an uplink optical transmitter control circuit, a mixing circuit and a data collection circuit. The radio frequency optical fiber transmission optical workstation has the advantages of small noise convergence, high bandwidth, property of being in line with IP-lization, low transformation cost per household and high reliability, and is convenient for upgrading and expansion.

Description

technical field [0001] The invention relates to a radio frequency optical fiber transmission (RFoG RF over glass) optical workstation used for the transformation of the two-way network of cable television, belonging to the technical field of cable television, in particular to a two-way transmission based on cable television for the transformation of a two-way network of a hybrid optical fiber coaxial cable network equipment. Background technique [0002] China Cable Television (CATV, Cable Television) has never faced challenges and development opportunities like it does today. The core business of CATV is facing direct competition from IPTV and satellite live broadcast, and its users are no longer satisfied with passive viewing of programs. , put forward diversified interactive entertainment requirements; the development of domestic digital TV in recent years has brought unprecedented development opportunities to the radio and television system. It provides a brand-new inte...

AI Technical Summary

Problems solved by technology

[0009] 1. Noise pooling: For most cable TV operators, upstream noise is a common problem, especially in low frequency bands (<65MHz)

Usually this kind of noise is caused by electronic motors, lightning, HAM, short-wave broadcasting or even sunspots, terminal boxes in the user's home, the quality of cables buried in the wall, private connection of non-standard parts, tape connection lines at various interfaces in the home, etc. It will destroy the data transmission of the uplink channel (reverse return channel), so as to reduce the user's communication quality, especially in real-time business situations such as video or IP voice, noise interference will cause data transmission delay and jitter, resulting in video Distorted picture or discontinuous voice

This requires that the coaxial cable connectors in the HFC network have a high electrical connection quality factor, and the technical support required for maintenance and operation troubleshooting is difficult to properly solve in the short term in most areas of our country

[0010] 2. Low bandwidth: using CMTS for two-way transformation, it is necessary to carry out two-way transformation on the optical receiver and amplifier (increase the reverse transmission module, reverse amplification module), and also need to add equipment such as reverse optical receiver and up-converter

[0011] 3. Does not conform to the trend of IP: CMTS adopts the multi-value quadrature amplitude modulation (MQAM) modulation method, which is essentially an analog network for transmitting radio frequency carrier signals, which runs counter to the network IP and Ethernet

[0012] 4. High cost per household: Although the coverage cost of CMTS is low, users need to be equipped with CM for broadband access and Internet access, and the price is relatively high

After the development of user scale, multiple CMTS users share 38M bandwidth, which cannot meet the needs of a large number of users, and the average cost per user is still high

[0013] 5. It is not easy to upgrade and expand: because the channels occupied by interactive services should not be too many, generally only 8 channels are arranged for the downlink

This method has a large number of front-end devices and complex maintenance and management, which puts great pressure on the upgrade and expansion of the back-end IP MAN.

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