专业英语复习试题及答案9-14单元

专业英语9-14单元复习试题及答案

一、Translate the following words into English.

1. 频谱

2. 激光束

3. 热核的

4. 数字模拟转换器

5. 数据库

6. 地球外的

7. 阻碍

8. 兼容性

9. 征兆10. 分开

11. 数字信号处理器12. 一致13. 基带14. 单色光的15. 卵石

二、Translate the following words and expressions into Chinese.

1. functional accelerator

2. acquisition time

3. low pass

4. hold time

5. anti-aliasing filter

6. quantization level

7. sampling interval

8. full scale range

9. dynamic range

10. signal-to-noise ratio 11. bus interfaces 12. wireless infrastructure 13. field-programmable

14. spectral inversion 15. price/performance ratio 16. under sampling 17. zero order hold

18. glue logic 19. power dissipation 20. sample and hold circuit

三、Fill in the blanks with suitable words from the list given below.

The first essential step in analog-to-digital (A/D) is to sample an analog signal. This step is performed by a sample and hold circuit, which samples at regular intervals called . The length of the sampling interval is the same as the sampling period , and the reciprocal of the is the sampling frequency f s. According to the Nyquist theorem, a signal with a maximum frequency of W Hz (called a band-limited signal) must be at least 2W samples per second to ensure accurate recording. When this minimum is not respected, called aliasing occurs.

R ①sampling intervals ②distortion ③conversion ④sampling period ⑤sampled

四、Comprehension. choose the best answer according to this passage.

Previously in this chapter, we’ve discussed how data elements (characters, fields, and records) c an be organized in files. In file-oriented systems, each file is independent and contains all the information necessary to process the records in that file. In a database, the data is organized in multiple related files. Because these files are related, us er can access data in multiple files at one time. A database management system (DBMS) is the software that allows the user to create, maintain, and report the data and file relationships. By contrast, a file management system is software that allows the user to create, maintain, and access one file at a time.

There are problems with traditional data management. Many result from viewing applications independently. For example, consider payroll. Most organizations prepare their payrolls by computer because using a machine instead of a small army of clerks saves money. Thus, the firm develops a payroll program to process a payroll file. Inventory, accounts receivable, accounts payable, and general ledger analysis are similar applications, so the firm develops program, and inventory file, an accounts receivable program, an accounts receivable file, and so on. Each program is independent, and each processes its own independent data file.

The solution to these problems is often organizing the data as a single, integrated database.

How does the use of a centralized database solve the data redundancy problem? All data are collected and stored in a single place; consequently, there is one and only one copy of any given data element. When the value of an element (an address, for example) changes, the single database copy is corrected. Any program requiring access to this data element gets the same value, because there is only one value.

1.In file-oriented systems, each file is independent and contains all the information necessary to process

the in that file.

A. elements

B. records

C. data

D. software

2. A database management system (DBMS) is the software that allows the user to create, maintain, and report

the and file relationships.

A. software

B. elements

C. data

D. records

3. The firm develops an inventory program to process .

A. data file

B. an accounts receivable file

C. a payroll file

D. an inventory file

4.The solution to these problems is .

A. changing the program