| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a signal switching device capable of automatically switching a signal output from a terrestrial analog broadcast signal to a retransmission signal of a headend device in accordance with the end of analog broadcast. <P>SOLUTION: The signal switching device includes a first signal input part for receiving a terrestrial analog broadcast signal, a second signal input part for receiving a terrestrial digital broadcast signal converted into a radio wave format of terrestrial analog broadcast, a signal switching means for switching signal outputs of the first and second signal input parts, a demodulating means for demodulating the terrestrial analog broadcast signal to output a video signal, and a control means for monitoring a vertical blanking interval of the video signal and controlling the signal switching means. The control means has a means for detecting a specific message included in a character broadcast program superimposed upon the vertical blanking interval, and switches a signal output in accordance with the detection of the specific message. Otherwise, the control means switches the signal output at timing when the character broadcast signal can not be decoded. <P>COPYRIGHT: (C)2010,JPO&INPIT |
