NTSC REMOVING FILTER IN PARALLEL STRUCTURE, AND METHOD FOR SIMULTANEOUSLY REMOVING NTSC INTERFERENCE SIGNALS, PARTICULARLY REGARDING TO ACCURATELY REMOVING NTSC INTERFERENCE BY USING SIMPLE NTSC REMOVING FILTER

摘要

PURPOSE: An NTSC removing filter in a parallel structure, and a method for simultaneously removing NTSC interference signals are provided to accurately remove NTSC interference by using a simple NTSC removing filter by processing the NTSC interference signals in parallel, and simultaneously removing the NTSC interference signals from original input signals. CONSTITUTION: A plurality of positive frequency shifters(402,404,406) shift input frequency spectra of DTV(Digital TV) signals in parallel as much as predetermined frequency amounts to arrange interference frequencies included in the input frequency spectra at a DC(Direct Current) component position. A plurality of DC detectors(412,414,416) are connected with the positive frequency shifters respectively, and detect DC components of the interference frequencies from the shifted input frequency spectra. A plurality of negative frequency shifters(422,424,426) are connected with the DC detectors respectively, and shift the DC components of the interference frequencies in an opposite direction of the frequency amounts. A summer(430) combines output frequency spectra of the negative frequency shifters. A subtracter(440) subtracts the output frequency spectra of the summer from the input frequency spectra.