High Precision Adjustable Electronically Controlled Equalization Circuit for CATV Network

Abstract

A high-precision adjustable electronically controlled equalization circuit for a cable television network, comprising one or more basic electronically controlled equalization modules with adjustable slopes, characterized in that it also includes a control module and one or more compensation modules, the control The module is electrically connected with the basic electronic control equalization module for controlling the slope change of the basic electric control equalization module, and the control module is electrically connected with the compensation module for generating a compensation signal according to the slope change of the basic electric control equalization module. The output of the equalization module is electrically connected to the input of the compensation module for outputting a complete signal after the two are superimposed. The high-precision adjustable electronically controlled equalization circuit of the cable TV network can obtain good signal waveform flatness at every slope.

Description

technical field [0001] The invention relates to the technical field of cable TV network, in particular to a high-precision adjustable electric control equalization circuit for cable TV network. Background technique [0002] In the CATV network (hereinafter referred to as CATV), the CATV signal will cause loss during the transmission of cables / optical fibers. Among them, the attenuation characteristic of the cable / optical fiber increases with the increase of the frequency, on the other hand, the attenuation of the signal increases with the increase of the distance of the cable / fiber. Therefore, for transmission cables / optical fibers with different distances, the transmission signal will have different attenuation slopes, which requires equalization circuits with different slope values ​​to equalize the attenuation of the signal and balance the in-band curve so that the signal can be transmitted stably and high-quality over long distances . [0003] In the downlink amplifier...

AI Technical Summary

Problems solved by technology

Compared with the first scheme, the second scheme has lower design cost, but both schemes need to be equipped with basic equalization modules or in-line attenuators with different slope values, which is not only inconvenient to operate, but also As the number of nodes used increases, the demand for basic equalization modules or in-line attenuators will also increase greatly, which will cost a lot of money in terms of cost and maintenance

[0004] But the electric control equalization circuit of existing cable TV network still has the following technical problems: because the slope variation range of electric control equalization circuit is bigger, usually between 0dB to 22dB, when the slope change of numerically controlled attenuator 1a like this, due to The change of impedance and the frequency response characteristics of the circuit itself lead to a large change in the flatness of the signal waveform at different slopes of the digitally controlled attenuator 1a, thereby affecting the characteristics of the transmitted signal. Therefore, it is urgent to design a new type of high-precision circuit control equalization circuit to solve the above technical problems

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