Integrated cascadable optical fiber tuner module

Abstract

The invention discloses an integrated cascadable optical fiber tuner module, relates to the technical field of the digital video broadcast, especially an optical fiber tuner module which is compact in structure, low in cost and supportable in cascading and an optical fiber set top box applying the module. The technical key point of the invention is that the module comprises a light source, an optical fiber access end, a photoelectric conversion circuit, an impedance matching circuit, a preamplifier, a denoising filter, a self-adaption signal enhancement circuit, a first automatic gain amplifier, a power divider, a frequency converter, a local frequency generation circuit, an intermediate-frequency filter, a second automatic gain amplifier, a demodulation circuit, a decoding circuit, a television signal leading-out end and a cascade signal leading-out end; the power supply supplies power to each electric component in the set top box ; the optical fiber access end, the photoelectric conversion circuit, the impedance matching circuit, the preamplifier and the denoising filter are sequentially connected.

Description

technical field [0001] The invention relates to the technical field of digital television broadcasting, in particular to a cascade-supporting optical fiber receiving tuner module and a cascade-supporting compact optical fiber set-top box circuit using the module. . Background technique [0002] The transmission and distribution of digital TV broadcasting signals in my country has roughly gone through three stages: [0003] The first stage: [0004] In the transmission and distribution of early digital TV broadcasting signals, the broadcasting signals were modulated and output from the digital front-end computer room, and then transmitted along the trunk cable. During the transmission process, a trunk amplifier was needed to amplify the signal. , need to increase the distributor and building amplifier, and then sent to the user's home through the splitter. [0005] Due to the large loss of electrical signals in cable transmission (about 25-40dB per 500 meters), a large num...

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Problems solved by technology

[0016] The optical receiver module and tuner module of the existing optical fiber set-top box are designed and produced according to the existing industry standard, and the existing industry standard is to meet the output of a single optical receiver module and the output of a single tuner module. The input can be adapted to as many types of access circuits as possible. In order to meet this requirement, the industry standard adds some circuit modules to the optical receiver module and the single tuner module. Such an optical receiver module When the group and coordinator modules are connected together, these circuit modules are not very effective, but increase the production cost and volume of the set-top box

[0017] In addition, the existing optical fiber set-top boxes cannot support the cascading function. However, with the improvement of social living standards, more and more families have more than two TV sets. For digital TV optical fiber set-top boxes, users need to install optical splitters in their own homes to split more optical fiber connectors to connect to more optical fiber set-top boxes. road, which greatly reduces the optical signal strength of the optical fiber set-top box connected to the optical fiber set-top box after the split, which seriously affects the TV reception effect of the optical fiber set-top box, resulting in mosaics; moreover, the user needs to destroy the home decoration, or directly use the optical fiber open line, and the construction is difficult Large, high technical complexity; what is more serious is that in this way, the non-fiber cable TV set-top box originally owned by the user needs to be eliminated, replaced or upgraded with peripheral equipment, which increases the burden on the user

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