| 摘要 |
PURPOSE:To output a television signal as a visible image whatever signal out of plural kinds of television signal different in the number of scanning lines and aspect ratio is inputted, by providing an input means which can input the first and the second television signals, a scanning line number converting means, and a means which switches the scanning speed in an output means. CONSTITUTION:The number of scanning lines of signals Rn, Gn, and Bn outputted from a decoder 2 is allowed to coincide with that of a high definition television signal (HD) by a number of scanning line converting circuit 3. A switch circuit 6 outputs signals Rn, Gn, and Bn or signals Rh, Gh, and Bh in accordance with the output of a mode switching circuit 10 and supplies them to an image receiving tube 8. Since they are different in horizontal scanning frequency, the center frequency of a control oscillator in a horizontal AFC circuit 16 is switched by a switch 21. Though deflecting coils 19 and 20 are driven by output signals of deflecting circuits 15 and 17, the voltage of the horizontal deflecting circuit 17 is switched by a switch 22 because NTSC and HD signals are different in aspect ratio. The output of the horizontal deflecting circuit 17 is supplied to a high voltage circuit 18 for driving the image receiving tube, and thus, pictures corresponding to HD and NTSC signals are displayed. |
