Patent ID: 8031269
Filing Date: 2011-10-04
Classification: H04N

Abstract:
1. A chroma killer detection circuit, comprising: a sampling circuit which receives a reference clock signal which has a frequency of four times of the burst signal which is generated from the color signal components which are digitized and which are synchronized with the burst signals and samples the cos θ components of the digitized color signal components on the (B-Y) axis, −cos θ components thereof on the −(B-Y) axis, sin θ components thereof on (R-Y) axis, and −sin θ components thereof on −(R-Y) axis; a cos θ components selection circuit for selecting cos θ components data among the data which are outputted from the sampling circuit, a first threshold value setting circuit for setting an arbitrary value on the (B-Y) axis which corresponds to the cos θ components data; a first comparator which compares the set value of the first threshold value setting circuit and the output data of the cos θ components data selection circuit and judges whether the cos θ components data on the (B-Y) axis are in abnormality state or in normal state from the comparison result; a −sin θ components data selection circuit which selects the −sin θ components data among the data which are outputted from the sampling circuit; a third threshold value setting circuit for setting an arbitrary value on the −(R-Y) axis corresponding to the −sin θ components data; a third comparator which compares the set value of the third threshold value setting circuit and the output data of the −sin θ components data selection circuit and judges whether the −sin θ components data on the −(R-Y) axis are in abnormality state or in normal state from the comparison result; a +sin θ components data selection circuit which selects the +sin θ components data among the data which are outputted from the sampling circuit; a fourth threshold value setting circuit for setting an arbitrary value on the +(R-Y) axis corresponding to the +sin θ components data; a fourth comparator which compares the set value of the fourth threshold value setting circuit and the output data of the +sin θ components data selection circuit and judges whether the +sin θ components data on the +(R-Y) axis are in abnormality state or in normal state from the comparison result; a judging circuit for judging normality or abnormality on the basis of the judgment result of the first comparator, the judgment result of the third comparator, and the judgment result of the fourth comparator; a counter circuit for counting the judgment result of the judgment circuit; a counter upper and lower limit detection circuit which observes the counted result of the counting circuit and outputs, when the counted value reaches a predetermined upper limit value or when the counted value reaches a predetermined lower limit value, a signal indicating that, respectively; a first killer judgment circuit which carries out killer judgment on the basis of the judgment result of the first comparator, the judgment result of the third comparator, the judgment result of the fourth comparator, and the output of the counter upper and lower limit value detection circuit; a second killer judgment circuit which carries out killer judgment on the basis of the judgment result of the first comparator, the judgment result of the third comparator, the judgment result of the fourth comparator, and the output of the counter upper and lower limit value detection circuit; and a killer judgment decoder circuit which decodes the results of the first killer judgment circuit and the second killer judgment circuit and generates a chroma killer signal indicating the broadcasting system of the received signal.