Signal distributor of cable television system

Abstract

A signal distributor of a cable television system is used for receiving a down message and transmitting an up message back to a cable television system operator, and comprises an electricity signal separating unit, an electricity conversion unit, a signal mixed separation unit, an up ASK (amplitude shift keying) transmission unit, a control unit, a signal output control unit, a signal distribution unit, a pirated connection detecting unit and a down FSK (frequency shift keying) receiving unit, wherein the up ASK transmission unit is a system control end to transmit the up message generated by the control unit due to the fact that the pirated connection detecting unit detects an abnormity to the cable television system operator by an ASK mode through the signal mixed separation unit and the electricity signal separating unit, thereby realizing a monitoring function; and the down FSK receiving unit transmits the down message by an FSK mode. The signal distributor can improve the transmission efficiency and avoid the multiple-harmonic influence.

Description

technical field [0001] The present invention relates to a signal distributor, in particular to transmit uplink information by way of Amplitude Shift Keying (ASK) to control the transmission of channel signals and to transmit downlink information by way of Frequency Shift Keying (FSK) To the system control terminal to monitor the channel signal. Background technique [0002] The channel signal transmission method of the general cable TV system is: use the broadcast system to generate the cable TV channel signal; send it to the signal distributor through the trunk distributor; use the modem to send the upstream information of the system control terminal to the broadcast system and the trunk distributor. The signal distributor; and the signal distributor controls whether to transmit the cable TV channel signal to the client TV according to the uplink information. In addition, in order to obtain the signal status of the client TV, the cable TV system operator uses an appropriat...

AI Technical Summary

Problems solved by technology

[0003] The signal distributor in the prior art has the function of controlling channel signal transmission and channel state return at the same time, and generally performs it in FSK mode, and it is difficult to completely filter out the multiple harmonics generated during the transmission process, making the channel state return When uploading, it will affect the specific channel screen

In addition, signal splitters often use PIN diodes as part of channel signal switching, and the cutoff effect is only about 30DB, so the signal cannot be completely shielded, causing the cable TV signal of the client TV to be interfered, resulting in noise displayed on the client TV The picture of snowflakes, especially the higher the frequency of the channel signal, the more serious it is

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