| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which it takes time to detect an unused user band signal.SOLUTION: An antenna device 101 and a plurality of receiving devices are connected with one cable. A receiving device 102 which receives a user band signal from the antenna device 101 through the cable receives the user band signal, when a power value corresponding to intensity of the user band signal which has passed through a band pass filter having mutually-different and adjacent frequency bands with identical and variable width is equal to or greater than a predetermined threshold, repeats processing for dividing the frequency band in which the power value is detected into n pieces, when the power value equal to or greater than the threshold is not detected over the adjacent frequency bands even though the frequency band width of the band pass filter becomes smaller than the band width of the user band signal per 1 channel, determines the frequency in which the power value is detected as the frequency which is not used in other receiving devices. |
