| 摘要 |
PURPOSE:To obtain electrically a sharp picture by changing a band variable low pass filter with an output of a variable voltage generating circuit so as to control the frequency characteristic of a luminance signal or the luminance signal and a chrominance signal. CONSTITUTION:A timing signal from a stop/start signal generator 5 changing a state into the state between sharp and unsharp state changes an output voltage of the variable voltage generating circuit 6. An output of the circuit 6 changes the band of variable low pass filters 7, 8 and 9 through which the luminance signal 2 and color difference signals R-Y3 and B-Y4 of the chrominance signal are passed respectively. Then the frequency band of the filters 7, 8 and 9 is changed from the frequency band required for the picture to become in the sharp state to the frequency band required for the picture to become in a the unsharp state in response to the potential of the timing signal. |
