| 摘要 |
<p>A color transmission system discrimination circuit capable of accurately and quickly discriminating a receiving color transmission system in a television set capable of receiving a plurality of television methods, the discrimination circuit comprising a killer status change detection circuit (23) for detecting changes in three kinds of color killer signals corresponding to a burst signal component at 90-degree phase, a burst signal component at 180-degree phase and an SECAM discrimination signal, a sequencer (22) which is started by an output signal from the detection circuit and executes in order first, second and third stages each for a specified time, first latch circuits (29 to 31) for latching a color killer signal captured in the first stage, second latch circuits (32 to 33) for latching a color killer signal captured in the second stage, and a discrimination decoder (34) for outputting a color system discrimination signal and a frequency discrimination signal of a reference sub-carrier signal based on a color killer signal captured in the third stage and output signals from first and second latch circuits (29 to 33).</p> |
