A method of detecting signal waveform disturbance in received television picture signal

摘要

For canceling ghost components disturbing a received picture signal waveform in the television transmission such as the television broadcast, ghost components of a reference pulse signal inserted at a central portion of a horizontal scanning period in a vertical blanking period of a picture signal is detected and then the received picture signal is processed such as those ghost components of the inserted reference signal are canceled by each other. In this signal processing, an auxiliary reference signal, the waveform and/or the level of which differ from those of the principal reference signal, the latter being occasionally almost zero, is inserted in a horizontal scanning period delayed from the principal reference signal by a repetition period after the lapse of which regular controlling signals such as synchronizing signals and color bursts having just the same waveform, level and phase reappear. In the differential signal waveform between received picture signals respectively neighboring both of reference signals, regular controlling signals are canceled by each other, while ghost components consisting of remaining waveforms except the difference between both of reference signals only are left, so as to facilitate the accurate detection of ghost components even exceedingly delayed over one half of a horizontal scanning period.