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调幅立体声技术的研究已有几十年的历史。早在二十年代,美国就着手对调幅立体声广播进行研究,但限于当时的技术条件,进展缓慢。进入七十年代以后,调频立体声广播得到迅速发展,调频立体声虽然音质好,但因使用在米波波段,在电波的传播和接收上都存在一些不足之处。出于竞争的目的,美国的一些调幅广播电台纷纷试用立体声广播,1975年,美国成立了全美调幅立体声广播委员会(NAMSRC),对调幅立体声广播进行了详细的研究。1980年4月,美国联邦通信委员会(FCC)决定,在全国试播的几种制式中,暂时选用 MAGNAVOX 作为全国的统一制式,但是这一决定立即遭到了各方面的强烈反对,迫使 FCC 重新研究,并于1982年3月决定,对已在试播的五种调幅立体声广播制式均予承认,暂不统一全国的制式,各种制式由市场的需求来判断其好坏。这五种制
Amplitude modulation stereo technology research has decades of history. As early as the 1920s, the United States set out to study amplitude modulated stereo broadcasting. However, due to the technical conditions prevailing at the time, the United States made slow progress. Into the seventies, the FM stereo broadcasting has been rapid development, FM stereo although good sound quality, but the use of the meter band, in the radio transmission and reception there are some shortcomings. For competition purposes, some AM radio stations in the United States have tried stereo broadcasting. In 1975, the United States established the National AM Stereo Broadcasting Committee (NAMSRC) to conduct a detailed study on AM stereo broadcasting. In April 1980, the Federal Communications Commission (FCC) decided that MAGNAVOX should be used for the time being as the national unified standard in several national pilot programs. However, this decision was immediately strongly opposed by all parties and forced the FCC to re-examine, In March 1982, it decided that the five types of AM broadcasting systems that have been piloted should be recognized and the national standards should not be unified for the time being. Various standards are judged by market demand to determine whether they are good or not. These five kinds of system