| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to receive VSB modulated signal and a QAM modulated signal by the same reception device without using different reception devices by switching a gain up to a detector among 8 VSB modulated signal reception of a digital ground wave broadcast, 16 VSB modulated signal of a digital CATV broadcast, and QAM modulated signal reception. SOLUTION: A VSB or QAM modulated signal is selected by a tuner, a signal inputted from a reception device input 1 has a channel selection frequency by an input filter 10 and is amplified by a 1st mixer 12 and converted in frequency into a 1st IF signal by a 1st mixer 12. Further, the 1st IF signal is selected by a 1st IF filter 14 and amplified and then a band-limiting filter 20 removes adjacent channel signal and a channel signal adjacent to the adjacent channel signal; when a 8 VSB modulated signal of a ground wave broadcast is received, it is passed through an amplifier 22 and when the 16 VSB of CATV and QAM modulated signal are received, they are inputted to a detector 23 not through the amplifier 22. |
