| 摘要 |
PURPOSE:To execute the highly reliable transmission stable in frequency characteristic by comparing a signal level of each frequency band with a reference signal level and automatically adjusting an equalizer of a main line electrically from the compared result. CONSTITUTION:A transmission signal is fetched from a branching device 4 provided on a main line 2, and the fetched signal is classified by frequency band with the aid of filters 5a, 5b, 5c.... Said filters are so constituted to pass through frequency bands f1, f2, f3..., and use, for instance, a pilot signal oscillated from a head end of the CATV system as a reference signal. Signals in an analog form from these filters 5a, 5b, 5c... are converted into digital signals in a control part 6, and the digital signals are compared with the reference signal. In accordance with the comparison, an equalizer 3, for instance, obtained by combining a coil with a voltage variable capacity capacitor, is electrically adjusted. |
