| 摘要 |
PROBLEM TO BE SOLVED: To output a terrestrial digital broadcast signal after canceling distortion such as level gradient in each channel band of the terrestrial digital broadcast signal. SOLUTION: In a channel level control unit 2, a received terrestrial digital broadcast signal is branched and then output as broadcast channel signals adjusted into specified level for each broadcast channel by channel level controllers 2a-2n, and the output broadcast channel signals are mixed by a mixer 30. In the channel level controller 2a, a specific broadcast channel signal separated by a band pass filter 16 is down-converted into an intermediate frequency (IF) signal by a mixer 18. For the IF signal, level tilting is then corrected to be flat by tilt circuits 24a, 24b and an unwanted component is removed by a SAW filter 25. The IF signal is up-converted into a frequency of the original broadcast channel signal by a mixer 26, and the broadcast channel signal is further level-adjusted into specified level by a level adjuster 28 and output through a band pass filter 29 to the mixer 30. COPYRIGHT: (C)2011,JPO&INPIT
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