Unit 2 Jobs and Careers In this unit, you will .first listen, and then learn to ask about job opportunities and go for job interviews; read about online job applications and first job experiences;

6-1数字调幅(ASK) 6-2数字调频(fsK 6-3、数字调相

一、二进制数字调制信号的功率谱密度 a)2ASK信号的功率谱密度 若二进制基带信号s(t)的功率谱密度P(f)为

Letter Writing Practice 2 Test Yourself You office needs to rent a video camera for one month. You need a small machine that produces a professional quality image. Write to Photofinish Ltd and ask them if they rent machines like that and the price. Write a full business letter. (invent any details you need)

习题一:1-4,1-5,1-6,1-7,1-9AD1-1 CAD1-1:用非线性VCVC实现一个幅度调制电路,如题图 CAD101所示。输入信号为两个不同频率的信号和, 输出实现两信号相乘,即EMOD=V1*V2。 设v1是50kHz的正弦信号,2是1kHz的调制信号。 要求得到标准调幅波SAM(调幅度mA=0.3和1.0) 抑制载波调幅波scAM 幅度键控调幅波ASK 并分析上述三种调幅波的特点

1) provide some clues to what makes a Nobel Prize Winner. 2) give guidance to learners to listen and talk about famous person. 3) provide students with new words and expressions 4) learn how to analyze word formation 5) ask learners to write in a chronological sequence

4.3.1 ASK或PAM信号传输的最佳检测和错误概率 4.3.2 PSK信号传输的最佳检测和错误概率 4.3.3 QAM信号传输的最佳检测和错误概率

4.3.1 ASK或PAM信号传输的最佳检测和错误概率 4.3.2 PSK信号传输的最佳检测和错误概率 4.3.3 QAM信号传输的最佳检测和错误概率

1 CPLD 可编程数字信号发生器实验 .3 2 模拟信号源实验 .6 3 调幅信号产生 .7 4 调幅波信号的解调 .11 5 脉冲编码调制与解调实验（PCM） .17 6 眼图测试实验 .24 7 二进制振幅键控（2ASK）调制与解调实验 .28 8 FSK 调制解调实验 .39 9 AMI/ HDB3 码编译码实验 .47 10 抽样定理验证与 PAM 调解实验 .55

In this unit, you will first listen, and then learn to ask about job opportunities and go for job interviews; read about online job applications and first job experiences; learn new words and expressions; write your own résumé; visit Culture Salon for some new terms in careers; check goals