| 摘要 |
A passenger aircraft video distribution system distributes modulated RF signals (lines 16,26) provided from a central signal source to be used at each passenger seat (208-1 through 208-15). The RF signals are distributed by means of various RF components, including amplifiers (14, 24, 34), taps and splitters (22, 30), positioned at different mutually distant stations (12, 18, 28), with at least some stations being interconnected by relatively long lengths of coaxial cable (16,26). In order to ensure proper RF levels for best tuner (36) operation and to compensate for different cable losses at different frequencies, one or more of the stations (18) in the distribution system is provided with a variable equalizer (23) controllable by a microprocessor (52). A separate service line (64,66) enables a central microprocessor (50) to monitor RF levels at different frequencies at at least one station (28) to automatically provide, via the same service line, appropriate equalization control signals to obtain proper compensation for the different cable losses at different frequencies. The monitored RF signals are also employed for diagnostic purposes. |
