| 摘要 |
PROBLEM TO BE SOLVED: To provide a receiver which quickly decides whether the broadcast is running on a selected channel to reduce the time required for selecting the television channel. SOLUTION: A first filter circuit 11 extracts a video intermediate frequency signal component of 58.75 MHz from an intermediate frequency signal IF, a second filter circuit 13 extracts a frequency component of a center signal of the intermediate frequency signal IF, a first level detector circuit 12 takes out the voltage value of the frequency component of the video intermediate frequency signal extracted by the filter circuit 11, a second level detector circuit 14 takes out the voltage value of the center signal frequency component extracted by the filter circuit 13, a comparator 15 compares these voltage values of the frequency components, and a signal existence decider 16 decides whether the level difference thereof is over a fixed value to determine that the broadcast wave exists on the channel and the broadcast is running, if the level difference is over the fixed value. COPYRIGHT: (C)2008,JPO&INPIT
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