Power-responsive ghost cancelling system

DETAILED DESCRIPTION Accordingly, it is an object of this invention to provide a ghost cancelling system which can obviate the aforesaid defects inherent in the prior art ghost cancelling system.
Another object of this invention is to provide a ghost cancelling system of simple arrangement capable of immediately activating analog accumulative adders to enable the quick convergence of the ghost cancelling operation.
Further object of this invention is to provide a ghost cancelling system which is free from the erroneous ghost cancelling operation, ensuring the prevention of a deteriorated picture.
According to an aspect of the present invention, there is provided a ghost cancelling system comprising: (A) signal input means for receiving an input signal which includes desired and ghost signals; (B) transversal filter means connected to said signal input means and responsive to said desired signal for forming a waveform corresponding to said ghost signal, said transversal filter means including a weighting circuit and memory means having a storage capacitor for storing a weighting function for said weighting circuit; (C) subtracting means connected between said signal input means and said transversal filter means for subtracting an output of said transversal filter means from said input signal; (D) a ghost detector connected between the output terminal of said subtracting means and said memory means for detecting a level of said ghost signal to control said memory means such that the weighting function changes in response to the detected level; (E) signal output means connected to the output terminal of said subtracting means; power responsive means for detecting the time when a power switch is turned on; and activating means connected between said power responsive means and said storage capacitor for charging the latter during a predetermined period when said power switch is turned on.
The other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings through which the like references designate the same elements and parts