Cable Two-way Hfc Network, Brings Together The Study Of The Problem Return

The optical fiber tran~nission. equipments and the fiber-cable production techniques have been applied to a wired television transmission network, thus replacing the long-distance cable main, and application of the co-axial cable advantages as of the transmission medium has formed a concept of Hybrid Fiber Cable (HFC) of the branch and going to-some place by distribution. Frequency band of the wired-television net widths nay reach the 5 to 750 MHZ, but the wired television network, in a traditional sense, is a unidirectional broadcasting network, but now reforming it into a bi-directional mutual broadcasting network whether in technique or in amount of work, is formidable, difficulty of which lies in the bi-directional mutual reverse transmission. In this paper, about how to realize the wired television bi-directional HFC network, technical problems of 搕he collecting disturbance?揷ollecting equalization? etc. present because of using the co-axial cable as transmission medium of the branch and going-to-some place by distribution have been solved, and beginning with the noise disturbance analysis, some methods and counta~measures of reforming and settling the problem have been put forward using part of experimental data and theoretic calculation. Utilization of filters having the back-transmission path equalization, and increasing the reversal blocking, adoption of star-connection network structure, and improvement of the construction technology and method of selection of materials cause the back-transmission noise to be decreased magnificently and guarantee the reliability of up-going signal. ?II ? This paper has introduced the hi-directional HFC network design and arrangement as well as testing and adjusting procedures in detail. At the same time, this paper has summarized the most important difference between the positive-direction and back-transmission designs & arrangements for information of persons of the same occupation.