| 摘要 |
PROBLEM TO BE SOLVED: To provide a band expanding system and a band expanding amplifier to apply that system in order to improve the data transmission efficiency. SOLUTION: Between transmission lines, branching filters 31 and 32 for branching high group down signals and low group up signals are located while facing. Then, a conventional amplifier 20 and an amplifier 36 are parallel connected to the outputs of these filters 33 and 37. These filters 33 and 37 and amplifier 36 constitute a band expanding amplifier 30. Then, the frequency characteristics of the filters 33 and 37 and the amplifier 36 are changed from that of a conventional network system. Namely, the frequency characteristics of the filters 33 and 37 are changed so as to shift a guard band to the side of high band. Thus, an upper limit on the side of a low band is shifted to the side of a high band. Namely, since the low band side (passband of low group up signals) is expanded, a new channel can be added and efficiency in the transmission of low group up signals is improved. |
