| 摘要 |
PURPOSE:To discriminate video signals whose frame frequencies are equal and whose effective scanning lines are different by detecting a signal level of a prescribed line of an input video signal. CONSTITUTION:In the case of transmitting a video signal of a studio standard by an MUSE(multiple sub-Nyquist sampling encoder) system, a video part allocated to a specific line is eliminated in a demodulated video signal. Therefore, by detecting the eliminated part of the video signal of the line, the kind of an input signal SE can be discriminated. Accordingly, by generating a video part discriminating pulse PSE, based on a horizontal synchronizing signal SH from a pulse generating circuit 10, and taking OR to a line discriminating signal SL, whether the video signal of the specific line exists or not is detected. In such a way, the video signal transmitted by the studio standard and the MUSE system is discriminated, and the video signal can be displayed surely. |
