| 摘要 |
PURPOSE:To obtain viewing channel information by providing a recognition section comparing and recognizing an output of a detection section detecting reception channel information and an output of a reference channel signal generating section to discriminate the received channel without applying any remolding or addition to a television receiver. CONSTITUTION:A detection section 1 is provided, which detects reception channel information such as synchronization of internal oscillation of a television receiver through the optical detection of raster scanning or high voltage leakage radiation of the television receiver, and a reference channel signal generation section 2 receiving a television channel separately, a synchronizing signal, a video signal or an audio signal is provided, and the recognition section comparing and recognizing the output of the detection section 1 with the output of the reference channel signal generation section 2 is provided. The high-voltage leakage radiation of the television receiver is an electromagnetic wave leaked from the high-voltage generating circuit for driving a cathode-ray tube and synchronizes with the received channel wave while having the horizontal oscillation frequency. The recognition section 3 consists of a comparator and an analog switch, outputs a coincidence signal when the synchronizing signals are coincident and the coincident channel becomes the viewing channel.
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