四川邮电职业技术学院教案专用纸 到目前为止在这个讨论中,我们一直假定每个话路各有一个编码器 和解码器前者是将幅度采样值变成脉冲而后者施行相反的变换这种设 置并非必需.在实际运行的PcM系统中,单一的编、译码器为24路、30路, 甚至120路所共用(注:在当代PQM设备中编、译码器系分路设备,即每 个话路各有一套.) (11). So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sampled amplitude values to a set of pulses; and decoder the unit that performs the reverse operation.本句理解和翻译应注意结构的分 析.在宾语从句 that each voice channel has…中has带了两个并列 的宾语 coder, decoder;且这两个成分又分别带了非限制性定语从句 A high-speed electronic switch(12a) is used to present the analog information signal of each channel, taken in turn(12b),to The codec is then arranged to sequentially sample the value, and code(12c) this value into the 8-digit sequence. 一个高速的电子开关被用来将每一话路的模拟信号依次地送往编、译 码器.然后编、译码器再顺序采样幅值并把这个幅值编成8位码序列 (12a). A high- speed electronic switch:一个高速电子开关 (14b). taken in turn轮流地,依次地 (12c), Code此处作动词,编码 Thus the output to the codec may be seen as a sequence of 8 pul relating to channel 1, then channel 2, and so on. This unit is called a time division multiplexer (TDM), and is illustrated in Fig. 1-2 (13). The multiplexing principle that is used is known as word interleaving. Since the words, or 8-digit sequences, are interleaved in time 因此从编译码器输出的信息就是一个分别对应于话路1,话路2,等 等的8位码序列.这种设备称为时分复用,如图1-2所示.音域8位码的 码字序列按时间顺序插接在一起,所以上面的复用原则称为码字插接 At the receive terminal a de-multiplexer is arranged to separate the 8-digit sequences into the appropriate(14)channels. The reader may ask, how does the de-multiplexer know which group of 8-digits relates to channel 1, 2, and so on? Clearly this important 接收端设置了分路设备将8位码序列分配到相应的话路中读者也许 会问,分路设备怎么知道哪一个8位码组对应于第1路、第2路极其他各 路呢?显然这是很重要的 (14). appropriate:adj适合的;适当的;相称的 appropria example适当的例子 appropriate manners适当的态度 Write in a style appropriate to your subject.用与你的题目相 Page 10 of 12 Teaching Plan of English for Telecommunications Unit On四川邮电职业技术学院教案专用纸 Page 10 of 12 Teaching Plan of English for Telecommunications Unit One 到目前为止,在这个讨论中, 我们一直假定每个话路各有一个编码器 和解码器.前者是将幅度采样值变成脉冲,而后者施行相反的变换,这种设 置并非必需.在实际运行的 PCM 系统中,单一的编、译码器为 24 路、30 路, 甚至 120 路所共用(注: 在当代 PCM 设备中,编、译码器系分路设备,即每 个话路各有一套.) （11）. So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sampled amplitude values to a set of pulses; and decoder, the unit that performs the reverse operation. 本句理解和翻译应注意结构的分 析． 在宾语从句 that each voice channel has…中 has 带了两个并列 的宾语 coder, decoder；且这两个成分又分别带了非限制性定语从句． A high-speed electronic switch (12a) is used to present the analog information signal of each channel, taken in turn (12b), to the codec. The codec is then arranged to sequentially sample the amplitude value, and code (12c) this value into the 8-digit sequence. 一个高速的电子开关被用来将每一话路的模拟信号依次地送往编、译 码器.然后编、译码器再顺序采样幅值并把这个幅值编成 8 位码序列. （12a）. A high-speed electronic switch : 一个高速电子开关 （14b）. taken in turn 轮流地，依次地 （12c）. Code 此处作动词，编码． Thus the output to the codec may be seen as a sequence of 8 pulses relating to channel 1, then channel 2, and so on. This unit is called a time division multiplexer (TDM), and is illustrated in Fig. 1-2 (13). The multiplexing principle that is used is known as word interleaving．Since the words, or 8-digit sequences, are interleaved in time. 因此从编译码器输出的信息就是一个分别对应于话路 1, 话路 2, 等 等的 8 位码序列. 这种设备称为时分复用,如图 1-2 所示. 音域 8 位码的 码字序列按时间顺序插接在一起,所以上面的复用原则称为码字插接. At the receive terminal a de-multiplexer is arranged to separate the 8-digit sequences into the appropriate (14) channels. The reader may ask, how does the de-multiplexer know which group of 8-digits relates to channel 1, 2, and so on? Clearly this is important! 接收端设置了分路设备,将 8 位码序列分配到相应的话路中.读者也许 会问,分路设备怎么知道哪一个 8 位码组对应于第 1 路、第 2 路极其他各 路呢?显然这是很重要的. （14）. appropriate: adj.适合的; 适当的; 相称的 appropriate example 适当的例子 appropriate manners 适当的态度 Write in a style appropriate to your subject.用与你的题目相