| 摘要 |
PROBLEM TO BE SOLVED: To provide an indoor booster for a bidirectional CATV system to decrease the up channel noises of a CATV system of a large scale and also to facilitate the investigation of factors for the up channel noises. SOLUTION: A gate switch 4 has an up amplifier 2 and a down amplifier 3 or only the amplifier 3 and performs pass/non-pass switching of signals to be inputted to turn on and off the output to be sent to the upstream, two or more band-pass filters 5 having different pass bands where only up signals of a desired band can pass among those input up signals, a variable attenuator 6 which adjusts an output level by attenuating the input up signals by the desired degrees and a control part 7 which performs the switching control of the switch 4 and the filter 5 according to the control signal that is inputted together with the down signals and detects the up signal levels to control the attenuation of the attenuator 6. In such a constitution, the part 7 can perform individual on/off control of both amplifiers 2 and 3 by a control signal. Furthermore, a variable equalizer 8 controls the band characteristics of input up signals.
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