问题 问答题 简答题

列出逻辑模拟中的主要延迟模型,并给出简单说明。

答案

参考答案:

元件的延迟模型和信号模型

元件的延迟模型:检查时序关系、反映竞争和冒险等现象;调用的门单元中已含有不同延迟模型信息。

零延迟:认为所有元件的延迟都为0,检查逻辑关系正确性,适合于组合逻辑和同步时序。

单位延迟:认为所有元件的延迟都相同,仅用于检查逻辑关系正确性。

指定延迟:不同元件或不同的元件类型指定不同的延迟;指定上升、下降时间;可用于尖峰分析。

最大-最小延迟:对每种元件指定最大和最小延迟时间,可用于分析电路出现竞争的条件。

惯性延迟:可抑制尖峰。

阅读理解

IMPROVE ON SLEEP

Good health needs good sleep. Going to bed before you’re tired. Not eating or reading in bed. Go to bed at the same time before midnight and get up at the same time. Your body likes routine (常规) for a good night’s sleep.

STAY FREE OF FLU

Brush your teeth twice daily and visit the dentist at least once a year. The mouth is a mirror of disease. The oral examination is not only for the health of teeth, but the whole body. For more of it, please visit www. mydr. com. au.

FIT FOR LIFE

Studies have shown that many diseases have something to do with less or no physical (身体) activity. Try to do it for 30 minutes a day, 5 days or more a week. For more information, please call HealthLine at 1800 438 2000。

小题1:If you want to get a good sleep, you’d better _______.

A.go to bed after you’re tired

B.go to sleep at midnight

C.follow the bedtime routine

D.eat something or read in bed小题2:To prevent from catching a cold or flu, it’s good for you _______.

A.to clean your fingers often

B.to brush your teeth twice daily

C.to get up early every morning

D.to wash all parts of your hands小题3:You should visit the dentist at least once a year, because _______.

A.the oral examination is necessary

B.you don’t often brush your teeth

C.some diseases may be in the mirror

D.you don’t have a good night’s sleep小题4:Studies have shown that many diseases have something to do with______.

A.having no oral examination

B.washing hands with cold water

C.sleeping too late sometimes

D.doing little physical activity小题5:When you want to learn more about the flu, you can _______.

A.visit www. mydr. com. au

B.call HealthLine at 1800 848 1313

C.visit the dentist in your place

D.call HealthLine at 1800 438 2000

选择题