更多"Spread spectrum simply means that d"的相关试题:
[单项选择]Spread spectrum simply means that data is sent in small pieces Over a number of the (46) frequencies available for use at any time in the specified range. Devices using (47) spread spectrum (DSSS) communicate by (48) each byte of data into several parts and sending them concurrently on different (49) . DSSS uses a lot of the available (50) , about 22 megahertz (MHz) .
A. continuous
B. high
C. low
D. discrete
[单项选择] To most Africans, tribalism simply means very strong loyalty to one’’s ethnic group. It is a force that can be both good and bad. By definition tribalism means sharing among members of the extended family. It makes sure that a person is taken care of by his own group. To give a job to a fellow tribesman is not wrong; it is an obligation. Similarly ,for a politician or military leader it is considered good common sense to choose his closest adviser from people of his own tribe. This ensures security, continuity, authority. Tribal loyalty may mean a quick promotion--from sergeant to captain, from clerk to manager--within a very short time.
Modern African politicians publicly speak out against tribal divisions. Yet it remains perhaps the most powerful force in day-to-day African life. As evidence of tribalism, in 1977 in Kenya, president Jomo Kenyatta’’s tribe controlled business and politics. Eight of the 21 cabinet posts, including the most important four were filled. by Kikuyus
A. Sharing among members of the extended family.
B. Giving a job to a fellow tribesman.
C. A force that can be both good and bad.
D. People have the same religious belief.