电视事业的发展,对电影业造成强烈的冲击。按有关国际版权的惯例,为维护电影业的利益与版权,在公共免费电视节目中,不允许播放尚在公映或仍保持有一定营业利润的影片,如须播放,则应向电影发行部门购买该影片的播出权,即交纳该影片播出的版权所有费。这样一来,电视台就已承付了该影片在全国或世界范围内的观众应交的票房费用,因此,收费制电视也就应运而生。 收费制电视通常多采用加密与加扰技术措施。例如,用特定的扰乱信号与正常信号相混合,进行载频发射,在接收 The development of the television industry has had a strong impact on the movie industry. According to international copyright practice, in order to safeguard the interests of the film industry and copyright, in the public free television programs, is not allowed to play still showing a certain operating profit of the film, if necessary, should be purchased from the film distribution department The right to broadcast the film, that is to pay the copyright fees broadcast on the film. As a result, the television station has already committed the film at the national or international audience should pay the box office fee, therefore, pay TV system also came into being. Pay TV system usually use encryption and scrambling technology measures. For example, a specific scrambling signal is mixed with a normal signal to carry a carrier frequency transmission. Upon reception