Title:
COLOR SIGNAL AMPLITUDE LIMITER FOR VIDEO SIGNAL
Document Type and Number:
Japanese Patent JP3158768
Kind Code:
B2
Abstract:
PURPOSE: To limit an amplitude of a video color signal without missing gradation and color change of a color signal after the amplitude is limited.
CONSTITUTION: A maximum value of color difference signals R-Y, B-Y subjected to color demodulation is detected by a 1st maximum value detection circuit 8, the value is compared with a reference voltage by a 1st comparator circuit 15 and when the maximum value exceeds the reference voltage, a switch circuit 10 is active. In this case, an output luminance signal (b) of a lightness adjustment circuit 4 is fed to a 1st adder circuit 11, in which the maximum value is added to a maximum value of a color difference signal through a color saturation adjustment circuit 2 to obtain a detection signal equal to an actual output signal of a matrix circuit 6. The peak level is detected over several fields by a peak detection circuit 12, a peak detection voltage (k) and an amplitude limit voltage λ are compared at a 2nd comparator circuit 13, and when the peak detection voltage (k) exceeds the amplitude limit voltage λ a color control signal of the are compared at the color saturation adjustment circuit 2 is decreased by a 2nd adder circuit 14 to decrease the color saturation.
Inventors:
Atsuhisa Kageyama
Naoki Okamoto
Naoki Okamoto
Application Number:
JP7550693A
Publication Date:
April 23, 2001
Filing Date:
April 01, 1993
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
H04N9/68; H04N9/64; (IPC1-7): H04N9/68
Domestic Patent References:
| JP2145084A | ||||
| JP530525A | ||||
| JP3201697A | ||||
| JP4957724A | ||||
| JP5866779U |
Attorney, Agent or Firm:
Fumio Iwahashi (2 others)