近二、三十年来，中、短波广播发射机的调制制式有了较大发展。继６种脉宽调制（ＰＤＭ）式调幅广播发射机依次由美、德、中、英、苏所创始，并各有不同程度的发展后，８０年代初，由瑞士勃郎·勃威力（简称ＢＢＣ、后改名ＡＢＢ）公司创造了脉冲阶梯调制式广播发射机，简... Nearly two or three decades, medium and shortwave broadcast transmitter modulation system has made great progress. Following the success of six kinds of pulse width modulation (PDM) AM transmitters, which were initiated by the United States, Germany, China, Britain and the Soviet Union and developed to some extent, respectively, in the early 1980s, the Swiss Broadcasting Corporation (“BBC” , Later renamed ABB) company created a pulse ladder modulated broadcast transmitter, Jane ...