Analog signal and digital signal are two kinds of signals in the form of control.

A . The three required steps in the analog to digital conversion are sampling，encoding，and compression. B . The three required steps in the analog to digital conversion are sampling，quantization，and compression. C . The three required steps in the analog to digital conversion are sampling，quantization，and encoding. D . The output of the sampling process is a pulse code modulation （PCM） signal. E . The output of the sampling process is a pulse amplitude modulation （PAM） signal.

A . the two steps of digital to analog conversion are decompression and reconstruction of the analog signal B . the two steps of digital to analog conversion are decoding and filtering C . the two steps of digital to analog conversion are decompression and filtering of the analog signal D . the two steps of digital to analog conversion are quantization and decoding

A . COSPAS-SARSAT B . ground receiving stations C . storing distress signal D . Near polar orbiting satellite

A . IP B . TCP C . RTP D . UDP E . H323 F . CRTP

A .  packetization B .  quantization C .  decoding D .  sampling

A . involution B . encoding C . sampling D . quantization E . compression F . companding

A . encountered B . met C . contacted D . see

A . sampling B . packetization C . quantization D . serializatio

A . raise the boom B . raise the hook C . raise the boom and hook D . check the boom sto

A . MP-BGP B . LDP C . Directed LDP D . MTP E . BGP F . IGP

A . Weekly Admiralty Notices to Mariners B . The Mariners Handbook C . Ocean Passages for the World D . Symbols and Abbreviations used on Admiralty Charts，Chart 5011

A .  involution B .  encoding C .  sampling D .  quantization E .  compression F .  companding

A．three B．seven C．eleven D．ten

A．12 B．10 C．8 D．6 E．1

Another example is photography: by the end of this year, tile number of images captured digitally each day is expected to surpass the number of images captured on film. With digital cameras and other devices linked to personal computers, we can collect vast amounts of data, which fortunately takes up little or no closet space. Today's average personal computer has a hard drive that can store 300 times more information than a decade ago. Technologies, such as broadband e-commerce, are expected to be the primary means of delivering entertainment and media by the end of this decade. Even life itself is increasingly digitized. The human genome(基因组), the recipe for our genetic makeup, has been mapped and encoded and researchers are harnessing the power of computing to accelerate the development, of new, lifesaving drugs. The implications of this broad, digital revolution are enormous, although they tend to be over-shadowed by the struggles of high-tech industries to recover from the go-go years of the 1990s. Those struggles are real, yet there are reasons for optimism about a return to robust economic growth and job creation in the next several years. The digital innovations(创新) of the past two decades continue to bear fruit, so stay tuned for good news--digitally, of course. Digital technologies really began to take form. when ______. A．information was encoded B．DVD technology was introduced C．it was used with photography D．used in computing

In partnering with the private Global Technology Organization, the UN Office for Projects Services wants to reduce the gap separating nations with good technology from those without. "There are more Web sites originating here in New York than in all of Africa," said Reinhart Helmke, executive director of the UN agency. "There are more Web sites originating in Finland than in all of Latin America and the Caribbean." Helmke said the digital divide would be better described as a digital chasm. He said the global economy cannot be sustained if some countries are left out. Neysan Rassekh, founder and president of Global Technology Organization, vowed to tackle the problem "country by country, town by town, citizen by citizen." The initiative carries no funding, however. The UN projects office, as a self-financing agency with a limited budget, will provide only management know-how. Rassekh's group, which organized the University of Pennsylvania group, plans to solicit(恳求) cash and equipment donations. For the Mali project, the university paid airfare and other expenses through fees that students pay to receive academic credit. Eliminating the global divide won't be easy. Persuading foreign governments to buy computers instead of food can be tough, even though technology can reduce poverty and hunger in the long run, said Hafidh Chaibi, who promotes global access through the World of Knowledge Foundation in Orlando, Fla. Ernest Wilson, an international development specialist at the University of Maryland, said his research found information technology growing by 18 percent a year in developing countries, compared with 23 percent in industrialized nations. That means the gap continues to grow despite improvements through programs from the United Nations, the World Bank, the Markle Foundation and other organizations. The UN announcement came as world leaders met at the UN Millennium Summit to discuss such challenges as peace, disarmament and access to new technology. Over four weeks in May and June, the University of Pennsylvania volunteers set up four computer centers in Mall and trained 120 residents, mostly students and educators who could then teach others. Organizers are also setting up a Web site to help residents obtain information on education and health. The UN agency and its private partner plan to replicate that effort in 10 to 12 countries a year. The "digital divide" as is used in the first passage refers to ______. A．the gap in technology and wealth between poor and rich countries B．inadequate training which technicians in poorer countries have received C．the availability of computer and Internet technologies to different nations D．the difference in the number of Web sites created to poor and rich countries

A．encode it by using the binary coding scheme B．quantize it in amplitude C．sample it at discrete time instant D．pass it through a D/A converte