| 摘要 |
PURPOSE:To discriminate abnormal operation by producing a digital signal corresponding to an AC component of an output signal of a waveform equalization circuit and counting the number of times where the level of the digital signal is inverted or the number of times where the same level is repeated continuously. CONSTITUTION:In case of ghost elimination of a television signal, for example, a flat part of an output signal is equal to noise n(t) and in applying difference processing to eliminate the DC component, its output becomes Y(t)=n(t-T)- n(t), where T is the time. In this case, the probability where the Y(t) is positive or negative is equal. In the oscillating state, on the contrary, an oscillated component Asinomegat is applied to the output signal and the probability where the Y(t) is continuously positive or negative is increased in the period of omega. Further, when the oscillation is larger, the probability where the Y(t) is biased positive or negative is increased. Thus, the abnormity is discriminated by counting the number of times of the level inversion or the number of times of consecutive same level at an abnormity detection circuit 70.
|
