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[单选题]
下列对通信系统进行差错控制的原因描述不正确的是( )
A
物理信道的突发噪声可能完全“淹没”一帧,即使得整个数据帧或反馈信息帧丢失,造成传输过程停滞b.由于网络传输中很难保证计时正确和一致,引起帧不同步c.同一帧数据可能重复发送多次,接收方可能多次收到同一帧并将其递交给网络层d.数据帧在传输过程中,线路本身电气特性生造成信号失真,出现差错
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试题答案:
B
答案解释:
【解析】信号在物理信道中传输时,线路本身电气特性造成的随机噪声、信号幅度的衰减、频率和相位的畸变、电气信号在线路上产生反射造成的回音效应、相邻线路间的干扰以及各种外界因素都会造成信号的失真。物理信道的突发噪声可能完全“淹没”一帧,即使得整个数据帧或反馈信息帧丢失,这将导致发送方永远收不到接收方发来的反馈信息,从而使传输过程停滞。由于同一帧数据可能被重复发送多次,就可能引起接收方多次收到同一帧并将其递交给网络层的危险。
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