| 摘要 |
<p>PROBLEM TO BE SOLVED: To appropriately transmit an incoming signal issued from a terminal side to a CATV center without providing an additional device on the subscriber' s side, in a CATV system for transmitting an incoming signal having a lower frequency band than a outgoing signal to the CATV center from the terminal side. SOLUTION: Among incoming signals transmitted from the terminal side, an incoming signal having a frequency band of 20 to 23.2 MHz which is outputted form a cable modem on the terminal side and tends to be mixed with mixed noises, is demodulated once by a center modem 36 in a local center modem 10, and a data signal from which a noise element is removed is extracted. Then, the data signal is modulated again by a cable modem 35, and it is sent to a lead-in wire 6 from an external connection terminal T1. An outgoing signal (40 to 55 MHz) which is outputted from an STB on the terminal side and is difficult to be mixed with mixed noises, is passed through via a BEF 33 and an HPF 32.</p> |
