| 摘要 |
PURPOSE:To block an unnecessary high frequency signal component by providing the 1st selector blocking a signal of an incoming frequency band and terminating the input of the 1st selector via the 2nd selector passing a signal of a frequency band blocked by the 1st selector. CONSTITUTION:A high pass filter (HPF) 117 passes an outgoing signal and blocks an incoming signal by deciding constants 109 116 and a low pass filter (LPF) 129 passes an incoming signal and blocks an outgoing signal by selecting constants 121 128. The outgoing signal inputted to an input terminal 101 passes through a fuse 106 and a capacitor 108 and is processed selectively by the HPF 117 and led to an output terminal 102. Since the LPD 129 is set so that the incoming signal frequency band only is passed, on outgoing signal flows to the LPF 129. When an unnecessary high frequency signal component at the incoming signal frequency band generated from a subscriber's equipment is fed to the output terminal 102, the invasion of the signal toward the input terminal 101 is blocked by the HPF 117. |
