第24题: [单项选择]正交相移键控调制(QPSK)()。 A. 调制效率高,要求传送途径的信噪比高,适合有线电视电缆传输 B. 调制效率高,要求传送途径的信噪比低,适合卫星广播 C. 抗多径传播效应好(即消除重影效果好),适合地面广播 参考答案:B
第25题: [单项选择]Questions 19 to 21 are bused on the conversation you have just heard. A. She specialized in short films. B. She featured famous actors. C. She told a long story. D. She used special effects. 参考答案:A 答案解析:[听力原文] 19-21 M: It seems that almost every city now has its own film festival. This is a good thi