PCM原理
抽样量化与编码:sampling,quantizing and coding
话路:speech channel

幅值: amplitude value
抽样频率: sampling frequency
抽样速率: sampling rate

脉冲流: stream of pulses
重复率: repetition rate

编码过程: coding process  
模拟信号: analog signal
传输质量: transmission quality
数字通信: digital communication
数字传输: digital transmission
含噪声的环境: noisy environment
传输路由: transmission path
信噪比 :signal-to-noise ratio
信号电平 :signal levels

噪声功率: noise power
地面系统: terrestrial system
二进制传输: binary transmission
反向操作: reverse operation
8-位码序列: 8-digit sequence
接受端: receiving terminal

帧格式 :frame format
同步字 :synchronization word
实现这三项功能的方案 :the schemes for performing these three functions
一串幅值: a series of amplitude values
电话质量的话路 a speech channel of telephone quality
一个8位二进制码的序列: a sequence of 8-binary digits
理论上的最小抽样频率 :a minimum theoretical sampling frequency
占据着300Hz到3.4kHz频率范围的话路: a voice channel occupying the range 300Hz to 3.4kHz
每个样值8-位码: 8-digits per sample value
汽车点火系统的打火: the sparking of a car ignition system
重复率为64kHz的脉冲流: the stream of the pulses with a repetition rate of 64kHz
真实信号与噪声信号的关系: relationship of the true signal to the noise signal
由卫星上接受到的信号 :the signal received from a satellite
一条特定消息中的全部信息 :the complete informatian about a particular message
被传信号的波形 :the shape of the transmitted signal
由传输路由引入的衰减: the attenuation introduced by transmission path
将抽样的幅值转换成一串脉冲的单元 :the unit that converts sampled amplitude value to a set of pulses
涉及到第一路，第二路及其他各路的序列: a sequence relating to channel 1,2 and so on
被称为同步字的独特码序列: a unique sequence of pulses called synchronization word
地面系统 :terrestrial system
脉冲的“有”或“无” : the presence or absence of the pulses
高速的电子开关: a high-speed electronic switch
时分多路复用器 :the time division multiplexer
时分多路复用 :Time Division Multiplexer

 

异步串行数据传输
串行接口 serial interface
显示终端 CRT terminal
发送器与接收器 transmitter and receiver
数据传输 data transmission
数据流 data stream
闲置状态 the idle state
传号电平 mark level
空号电位 space level
起始位 start bit
停止位 stop bit
T秒的持续时间 duration of T seconds
奇偶校检位 parity bit
错误标志 error flag
传输错误 transmission error
下降沿 fallinf edge
符号间的空格 intersymbol space
接收机的定时 receiver timing
本地时钟 local clock
磁带 magnetic tape
控制比特 control bit
逻辑1电平 logical 1 level
二进制数据 binary data
明显的缺点 obvious disadvantage
异步串行数据传输 asynchronous serial data transmission
最为流行的串行接口 the most popular serial interface
所传送的数据 the transmitted data
发送器与接收器的时钟 the clocks at the transmitter and receiver
电传机的时代 the era of teleprinter
一个字符的点和划 the dots and dashs of a character
符号间空格持续时间的三倍 three times the duration of intersymbol space
被称为字符的比特组 the group of bits called characters
由7或8个比特的信息组成的固定单元 the invariable units comprising 7 or 8 bits of information
由接收机本地产生的时钟 a clock generated locally by the receiver
在字符后所收到的奇偶校检位 the received parity bit following the character
起始位的下降沿 the falling edge of the start bit
数据链路面向字符的特性 the character-oriented nature of the data link