外文翻譯----調(diào)幅無線電

1、<p><b>　　畢業(yè)設(shè)計(jì)/論文</b></p><p>　　外 文 文 獻(xiàn) 翻 譯</p><p>　　系　 別 信息科學(xué)與技術(shù)系 </p><p>　　專 業(yè) 班 級(jí) 電子信息工程0601 　　 </p><p><

2、;b>　　調(diào)幅無線電</b></p><p>　　歷史Main articles: History of radio anOldest radio station</p><p>　　無線電的歷史及早期的無線電電臺(tái)AM was the dominant method of broadcasting during the first eighty years of the

3、20th century and remains widely used into the 21st.可以追溯到可以可以追溯到20世紀(jì)前八十年 ，利用調(diào)幅無線電通信進(jìn)行廣播是非常有效的方式，進(jìn)入二十一世紀(jì)，這一方式，仍被廣泛采用。 AM radio began with the first, experimental broadcast on Christmas Eve of 1906 by Canadian experimenter

4、Reginald Fessenden , and was used for small-scale voice and music broadcasts up until World War I . San Francisco, California radio station KCBS claims to be the direct descendant of KQ</p><p>　　[ edit ] Ope

5、ration AM radio technology is simpler than FM radio , DAB , Satellite Radio and HD Radio 調(diào)幅收音機(jī)的技術(shù)要比調(diào)頻收音機(jī)、DAB、衛(wèi)星廣播和高清廣播簡(jiǎn)單得多。An AM receiver detects amplitude variations in the radio waves at a particular frequency. It t

6、hen amplifies changes in the signal voltage to drive a loudspeaker or earphones 一個(gè)調(diào)幅接收器在一個(gè)特定頻率檢測(cè)無線電波的振幅變化。然后通過放大信號(hào)電壓來驅(qū)動(dòng)揚(yáng)聲器或耳機(jī)。最早的 晶體收音機(jī)接收器 使用沒有放大功能的 晶體二極管探測(cè)器。In North American broadcasting practice, transmitter power inp

7、ut to the antenna for commercial AM stations ran</p><p>　　Frequency bands頻帶 </p><p>　　AM radio is broadcast on several frequency bands.調(diào)幅廣播的節(jié)目于多個(gè)頻帶。這些頻段的分配是由國(guó)際電聯(lián) '管擰 無線電管理?xiàng)l例 ，并在國(guó)家一級(jí)，每個(gè)國(guó)家的電信管

8、理（即 聯(lián)邦通訊委員會(huì) 在 美國(guó) ，例如）受國(guó)際協(xié)定。 Long wave is 148.5 kHz –283.5 kHz, with 9 kHz channel spacing generally used.長(zhǎng)波 是148.5 千赫 -283.5千赫頻率間隔為9普遍使用的渠道。長(zhǎng)波用于無線電廣播的歐洲，非洲和亞洲部分地區(qū)（ 國(guó)際電聯(lián)地區(qū) 1），而不是在西半球分配。在美國(guó)和加拿大，百慕大和美國(guó)領(lǐng)土這個(gè)頻段主要用于航空預(yù)留導(dǎo)航設(shè)備雖然是樂

9、隊(duì)的一小部分在理論上可用于在美國(guó)部分 microbroadcasting 15 規(guī)則。由于長(zhǎng)波信號(hào)的傳播特性，使用的頻率是最有效地在緯度50度以北。 Medium wave is 520 kHz–1,610 kHz.中波 520千赫 -1，610千赫。 In the Americas (ITU region 2) 10 kHz spacing is </p><p>　　[ edit ] Limitations局

10、限性</p><p>　　Because of its susceptibility to atmospheric and electrical interference, AM broadcasting now attracts mainly talk radio and news programming, while music radio and public radio mostly shifted to

11、 FM broadcasting in the late 1970s.因?yàn)樗菀资艽髿夂碗姎飧蓴_，調(diào)幅廣播現(xiàn)在吸引主要談話類節(jié)目和 新聞節(jié)目，而音樂電臺(tái)和公共廣播大多轉(zhuǎn)向70年代末的調(diào)頻廣播。然而，在1960年代末和70年代，前40巖石，如WABC和覃德在美國(guó)和加拿大推出臺(tái)發(fā)射的高度加工和延長(zhǎng)至11 kHz的音頻，成功地吸引了大量觀眾。在英國(guó)，20世紀(jì)80年代 ，BBC廣播4臺(tái)（一大部分講話頻道）有一個(gè)調(diào)頻的位置，而英國(guó)廣播公司電臺(tái)第一

12、 ，音樂頻道，只限于在英國(guó)多為AM廣播。頻率響應(yīng)通常是40赫茲- 5150 分貝 千赫S/N比。The limitation on AM fidelity comes f</p><p><b>　　其他應(yīng)用方式</b></p><p>　　Stereo transmissions are possible (see AM stereo ), and hybrid d

13、igital broadcast systems are now being used around the world.立體聲 傳輸（見 AM立體聲 ），和混合數(shù)字廣播系統(tǒng)是可能并正被廣泛采用于世界各地。在美國(guó)，iBiquity公司 的專有 高清收音機(jī) 已被采納和聯(lián)邦通訊委員會(huì)批準(zhǔn)的中波轉(zhuǎn)播，而數(shù)字無線電廣播通用 經(jīng)常在 短波波段 使用是將一個(gè)更加開放的努力 ，并且將與眾多調(diào)幅廣播并行使用。這些標(biāo)準(zhǔn)都比當(dāng)下的調(diào)幅帶寬限制以及0-16千

14、赫頻率響應(yīng)的理論有著更高質(zhì)量的保真度，除了立體聲聲音和文字?jǐn)?shù)據(jù)。While FM radio can also be received by cable , AM radio generally cannot, although an AM station can be converted into an FM cable signal雖然調(diào)頻收音機(jī)也可以通過 有線電視 接收 ，調(diào)幅收音機(jī)一般不能，雖然是調(diào)幅站能夠通過有線調(diào)頻信<

15、/p><p>　　[ edit ] Microbroadcasting微型發(fā)射機(jī) </p><p><b>　　微型發(fā)射機(jī)</b></p><p>　　Some microbroadcasters and pirate radio broadcasters, especially those in the United States under t

16、he FCC's Part 15 rules, broadcast on AM to achieve greater range than is possible on the FM band .一些微型發(fā)射機(jī)和 海盜電臺(tái)廣播，特別是美國(guó)的根據(jù)FCC的 第15章 規(guī)定，對(duì)AM廣播實(shí)現(xiàn)更大范圍比在 調(diào)頻波段 的可能。在中波（調(diào)幅），這些電臺(tái)經(jīng)常能在1610千赫和1710千赫間被探測(cè)到。Hobbyists also use low-

17、power AM transmitters to provide local programming for antique radio equipment in areas where AM programming is not widely available or is of questionable quality; in such cases the tra</p><p>　　AM broadcast

18、ing</p><p><b>　　History</b></p><p>　　AM was the dominant method of broadcasting during the first eighty years of the 20th century and remains widely used into the 21st.AM radio began

19、 with the first, experimental broadcast on Christmas Eve of 1906 by Canadian experimenter Reginald Fessenden, and was used for small-scale voice and music broadcasts up until World War I. San Francisco, California radio

20、station KCBS claims to be the direct descendant of KQW, founded by radio experimenter Charles "Doc" Herrold, who made regular weekly br</p><p>　　Operation </p><p>　　AM radio technology

21、 is simpler than FM radio, DAB, Satellite Radio and HD Radio. An AM receiver detects amplitude variations in the radio waves at a particular frequency. It then amplifies changes in the signal voltage to drive a loudspeak

22、er or earphones. The earliest crystal radio receivers used a crystal diode detector with no amplification.</p><p>　　In North American broadcasting practice, transmitter power input to the antenna for commerc

23、ial AM stations ranges from about 250 watts to 50,000 watts. Experimental licenses were issued for up to 500,000 watts radiated power, for stations intended for wide-area communication during disasters including Cincinna

24、ti station WLW, which used such power on occasion before World War II. WLW's superpower transmitter still exists at the station's suburban transmitter site, but it was decommissioned in the</p><p>　　

25、Frequency bandsAM radio is broadcast on several frequency bands. The allocation of these bands is governed by the ITU's Radio Regulations and, on the national level, by each country's telecommunications administr

26、ation (the FCC in the U.S., for example) subject to international agreements.Long wave is 148.5 kHz–283.5 kHz, with 9 kHz channel spacing generally used. Long wave is used for radio broadcasting in Europe, Africa and par

27、ts of Asia (ITU region 1), and is not allocated in the Western Hemis</p><p>　　Limitations </p><p>　　Because of its susceptibility to atmospheric and electrical interference, AM broadcasting now

28、attracts mainly talk radio and news programming, while music radio and public radio mostly shifted to FM broadcasting in the late 1970s. However, in the late 1960s and 1970s, top 40 rock and roll stations in the US and C

29、anada such as WABC and CHUM transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. In the UK during the 1980s, BBC Radio 4 (a largely speech c</p><p>　　Other distr

30、ibution methods </p><p>　　Stereo transmissions are possible (see AM stereo), and hybrid digital broadcast systems are now being used around the world. In the United States, iBiquity's proprietary HD Radi

31、o has been adopted and approved by the FCC for medium wave transmissions, while Digital Radio Mondiale is a more open effort often used on the shortwave bands, and can be used alongside many AM broadcasts. Both of these

32、standards are capable of broadcasting audio of significantly greater fidelity than that of standard AM </p><p>　　Microbroadcasting </p><p>　　Some microbroadcasters and pirate radio broadcasters,

33、 especially those in the United States under the FCC's Part 15 rules, broadcast on AM to achieve greater range than is possible on the FM band. On mediumwave (AM), such radio stations are often found between 1610 kHz

34、 and 1710 kHz. Hobbyists also use low-power AM transmitters to provide local programming for antique radio equipment in areas where AM programming is not widely available or is of questionable quality; in such cases the