问题 问答题 简答题

说明Walsh码在IS-95A上下行链路中的作用分别是什么?什么是64阶正交调制。

答案

参考答案:

上行链路:用Walsh码经行64阶正交调制,用长度为2^42-1的PN长码序列区分用户。下行链路:用Walsh码经行64阶正交调制,用相位不同的长码序列区分信道。

64阶正交调制:用正交码为64阶的Walsh函数,生成Walsh序列长度为64个码片。正交信号共有64个Walsh码型,可提供的码分物理信道共64个。

阅读理解

Some students, parents and teachers in Shanghai were surveyed last month. According to the result of the survey, the generation gap (代沟) between students and parents as well as teachers is becoming wider. Here is what they said.

Voice of the students:

  “Our parents hold too high expectations(期望)which put us under lots of pressure. They care too much about our lives and studies,” one student said.

“It’s impolite that some students’ parents read their children’s diaries without permission!” one student said angrily.

“Some of our teachers are so serious that we can’t make friends with them at all,” another student said sadly.

Voice of the parents:

One mother said, “After school, my daughter usually locks herself into her room and spends lots of time talking with others on the phone. And I can’t stand(忍受) her clothes and hairstyle!”

“I thought my son was doing very well in his studies. I didn’t realize I was being cheated by him until I got a call from his teacher,” said a father.

Voice of the teachers:

An English teacher said, “Today, the role of the teacher is to put knowledge into students’ brain. The power (权力) teachers have kept students away from them.”

“Some parents pay too much attention to their children’s grades instead of creating a lively and colorful environment at home,” another teacher said.

“In the past, teachers and students often played games together or talked with each other. Today, only studies and grades are talked about,” said a teacher. “A school should be a place where students can learn not only knowledge, but also how to face failure and frustration(挫折) bravely enough.” 

小题1: What does the first paragraph mainly tell us?

A.Students like telling how they feel to their classmates.

B.More and more students don’t like to be surveyed.

C.Some parents don’t like their children’s clothes and hairstyle.

D.There has been a great distance between students and parents as well as teachers.小题2:The underlined word “cheated” in the passage means ___________.

A.欺骗

B.批评

C.表扬

D.揭露小题3: What can we infer (推断) from the teachers who were surveyed?

A.Teachers feel what they are doing for students is good.

B.Parents, teachers and educational rules all influence students greatly.

C.Teachers should care more about excellent students.

D.Now teachers and students communicate better than before.小题4:Which of the following could be the best title for the passage?

A.Unhappy Teenagers

B.Educational Rules

C.The Generation Gap

D.Serious Parents

单项选择题