毕业设计(论文)外文翻译李宏成.doc

江西理工大学应用科学学院毕业设计(论文)外文资料翻译系 别： 信息 专 业： 电子信息工程 班 级： 081 姓 名： 李宏成 学 号： 08060308116 附 件：1.外文资料翻译译文；2外文原文指导教师评语： 签名： 年 月 日Dolby laboratory on DolbyAuthor: TigerMultichannel perceptual codingDolby AC-3is a kind of efficiency, quality and functional aspects with unprecedented effect perceptual digital audio coding technology. From the beginning of 1992, it has been for the cinema provide multichannel digital audio system and achieved in 1994into the two channel I BS application. It in the cassette and disc type family television system for transmitting multichannel digital sound function has been to the consumer electronics industry with very excited. In the United States, high definition television ( HDTV ) broadcasting the selected Dolby digital surround sound transmission, estimated that in 1996will be put into a test screening.Many have been announced and the potential applications of the technology of test shows, Dolby AC-3decoder has a beautifully versatility. AC-3 is not a single machine system, but a kind of use can make such as bit rate and number of channels such parameters to adapt to different special application flexible procedures for the treatment of familial. Various types of all decoder in order to work on the same principle as the foundation, and designed to take full account of the future need for compatibility and adaptability. Important is, Dolby AC-3will be high quality sound and excellent digital efficiency is very perfect combination. Because of the Dolby Laboratory for more than 20 years focus on human auditory research, in the development of signal processing field has accumulated rich experience, so, although AC-3than in the CD disk to the last channel lower bit rate to create a multi-channel surround sound, however, it makes the sound quality fully meet the listener expectations.Audio : past present and futureIn 30, the famous Baer Laboratories began using the three channel stereo sound. In 50, when the stereo into public movie, it uses the channel in four above, sometimes reaching over seven channels. A few years later, the stereo into families, since all of the phonograph records only with dual channel matching, so the family leave acoustic device only by dual channel playback, the technical limitations, can not the listener will generally two-channel stereo as the home audio selection criteria.But the film makers have channel 1( left, right, center ) and surround channel2as a compelling vivid sound minimum requirements. This can be from 70 time end, eighty time period the film industry widely adopted Dolby stereo to record film confirmed, Dolby stereo is the principle, let four channel matrix coding input two optical sound track, then an appropriate audio processor will restore it into four channels matrix coding reproduction.When Dolby stereo film is converted into audio signals, four channel coding retained the dubbing integrity, from 80 time begin first, Dolby surround has made multiple channel decoding into family time, today, tens of thousands of home audio systems are equipped with Dolby surround sound system, in fact, multi-channel surround sound system sales has been far beyond the two-channel stereo system sales, at present, Dolby surround sound has been widely used in film, TV and music on CD recording studio, and its accompanying family Dolby surround systems on the market rapid development.With multi-channel audio in consumer electronics in the field of rapid growth, a more advanced technology was born, the technology is born there is nothing comparable to this, it has simulated realistic sound effects, and can satisfy various listening conditions and high demand cannot imagine adaptability, this is Dolby AC-3decoding technology Dolby AC-3 decoder, the successful development and application, is the world's electro-acoustic industry a major achievement.Dolby AC-3In 1987, high-definition television channel in the United States has officially become the standard process, its audio track is used for the first time in the four channel matrix encoding conversion for transmission of digital code stereo. However, by 1990, in order to avoid audio matrix are affected, four mono or stereo combined configuration as the optimal configuration. Due to time technical limitations, such an arrangement would have to increase by at least a bit rate.It is in this context, Dolby AC-3was born. It has the advantage of only two independent stereo more code rates can realize multi-channel audio code. Dolby advanced to the transmission of the code technology, such as Dolby AC-2 decoder for Dolby AC-3's successful development paved the way, but the complexity of multichannel code also need further research, including a new type of bit allocation technique.The Dolby laboratory is established by Rui Milton Dolby. Dr. Dolby was born in 1933 in the United States Portland Oregon City, grew up in the San Francisco Bay area. At the age of 16 he was still in high school, in Ampex company works. The company is the United States 's first production of magnetic tape recording equipment manufacturers. Later, he is responsible for the development of the company developed the world's first practical VCR portion of an electronic circuit.In 1957 Dolby graduated from Stanford University, University of Cambridge, Marshall won the British provided scholarships, study of L-band X light. In 1961 he received a doctor's degree in physics. In 1963, he accepted the UN appointed to India as a two-year consultant.As an amateur recording enthusiasts, Dr. Dolby over the years to recognize on the tape recording audio or video signal when background noise on the recording quality damage. While in India he began thinking seriously about a noise reduction without compromising the recording quality approach. His exploration of these became the Dolby A B noise reduction and noise reduction, noise reduction system based on C.In 1965, returning to England, in London he established his own laboratory in order to carry out in India he thought scheme. Set up in 1968 to" the Dolby lab" named company. Although the company was founded10 years ago, the work of the centre in the UK, but it has been an American company. After 1976, the company's main work moved to San francisco.In 1965, the first Dolby A type noise reducer ( A representing audio Audio ) production out of. The design of the system for a variety of audio noise reduction application, especially can solve the studio recording tape when the tape recorder generated noise. Until 1966, there have been several noise reducing technology available, but they are much to damage the recording quality. So Dr Dolby faced difficulty is how to make the personage inside course of study and potential customers to believe his technique. At that time, multitrack recorder, from the 4 rail, track 8, track 16to 24 track, start the application, when multitrack recording tape audio mixing, the mixing of the two track tape noise level than double direct recording of the master tape is much higher.In 1966January, Decca Records UK Department believes that Dolby A type noise reducer can indeed as Dr. Dolby described that play a role, and then ordered9Dolby A301A type noise reducer, applied for the first time in 1966May in Vienna to record Ashe Ken that Qi played some of Mozart's piano concerto. In 1966November, Decca published the first application of Dolby A type noise reducer record by Georg Solti / Muller second symphony.Subsequently, the recording industry began to recognize and use a large amount of Dolby A type noise reduction system. Initially used only recorded classical music, when multitrack recording technology promotion, will be more widely applied. Soon, the whole world of professional and non-professional begin to" Dolby" with high quality recording together.With the hope that Dolby will be present and noise reduction technology for civilian recorder voice rising, in an American commercial tape recorder manufacturer KLH company 's urging,1967April Dolby lab started to develop more practical civil noise reduction technology, initially known as the" simplified Dolby system", which later became known as Dolby B type noise reduction technology. In the Dolby B noise reduction technology development is nearing completion, Dr. Dolby made the decision, Dolby laboratory will not civilian production of audio products, consumer electronics products, but to the manufacturers authorized Dolby technology has been very mature, then by manufacturers for production. By the end of 1974, the Dolby laboratory authorized manufacturers already amounted to 47, including all consumer audio equipment manufacturers.Thereafter, Dolby laboratory has developed a series of Technology: C type noise reduction, SR ( spectral recording ), S type noise reduction, HXPro, stereo surround Dolby, Dolby, Dolby Pro Logic, AC1, AC2, Dolby digital ( AC3), Dolby E. These techniques are widely used in civil and professional audio equipment, sound recording film, cinema playback apparatus, digital broadcast etc.In addition to the headquarters in San Francisco, Dolby laboratory at present in the world have established branches or liaison offices: Losangeles, Wootton Barcelona ( UK), London, Brisbane, New York, Tokyo, Shanghai, Beijing, Hongkong. 翻译结果重试抱歉，系统响应超时，请稍后再试支持中英、中日在线互译支持网页翻译，在输入框输入网页地址即可提供一键清空、复制功能、支持双语对照查看，使您体验更加流畅AC-3 multi-channel frameDolby surround ( Dolby Surround ) is the original Dolby multichannel film analog format consumer version. In the production of Dolby surround sound, a 4Channel - left, right, and surround sound channel audio information through matrix coding in two tracks on a record. The two tracks from stereo format program source such as a video and television broadcast program and carrying into the family, and decoded the original 4channels of information can be reduced and surround sound. Hundreds of thousands of home videos and TV shows by Dolby surround coding." Dolby surround ( Dolby Surround ) as the most primary surround sound standard, provides a 4channel surround sound support.Dolby surround and DTS surround is similar in that they are lossy digital compression technology. This is referred to as" emotional" data compression technique is based on the human psychoacoustics that possess sound characteristics - for high level sensitive voices, while shielding the other is not sensitive to the sound development of.Because Dolby stereo is a coding technology of digital stereo, and decoding technique uses a direction identifying circuit or a directional logic circuit, so that the use of Dolby company this circuit technology of sound is called Dolby Pro Logic sound; with Dolby 's proprietary specific decoding technology is called a Dolby Pro logic decoder decoder.Of course, only with the use of Dolby to the logic function of the AV amplifier, played by Dolby sound recording software, can hear the true high fidelity digital stereo sound effect.Dolby digital systems will generally be5.1 channel sound compression to 384bps, and some CD with 448bps, the maximum to the 640bps; DTS usually use much larger bit rate -1536bps. If other conditions are the same, is a bit more quality is better, this assertion is wrong? Unfortunately, the answer to this question is not so easy, because the Dolby Digital ( abbreviated as DD ) and DTS data compression circuit is different. For example, a coding efficiency very low signal, even if the bit rate is very high, also just wasted bits and disc space, but does not improve sound quality. Once a system is said to be" transparent", increase the bit rate without causing it to improve the sound quality. In addition because the DTS bit rate higher than Dolby, need takes up more space, if the DVD disk capacity constraints, may produce adverse effects on image quality, or to increase the additional cd.Dolby Pro-Logic surround sound ( Dolby Pro Logic ) is Dolby developed a surround sound system. It is the four track stereo recording by a specific encoding means for the synthesis of two channel, the original left channel ( L ), the right channel ( R ), the center channel ( C ), surround channel ( S ) of the 4signal, encoded into LT, RT composite double channel signal, replay through the decoder will encoded two-channel composite signals LT and RT reduction for encoding the left, right, in around four, each stem and independent signal, amplified respectively input left, right, center and surround sound speakers.In order to playback symmetry reasons, surround speakers using the left and right surround speakers, respectively, from the output of the amplifier, so the business to Dolby Pro-Logic surround sound output called channel five. But due to a left, right surround sound speakers connected in a channel, the output is the same as the surround channel information, the essence is still four channel. The business also has six channels and seven channels Dolby Pro Logic AV amplifier. The six track is the central channel two amplifying circuit is respectively connected with the output, in left center speaker and right center speaker. But left, right center speaker connected to a center channel, it is essentially a four channel. Seven channel surround sound channels is divided into four channel output, i.e. left rear surround, right rear surround sound, and adopts four surround sound, which became a seven channel output. But the output of the seven track four surround speakers are connected in a surround channel, also can calculate the output of four sound channels. So with Dolby Pro logic decoder AV amplifier whether five channel output, six channels of output or the seven output channels, is essentially a four channel. Dolby Pro-Logic surround sound in the left, right, three channel frequency range can reach 20-20000Hz, can meet the full range of requirements, but surround channel frequency range is narrow, only 100-7000Hz.Dolby E is designed for digital TV broadcast and post-production and the design of a professional audio coding system. Using the Dolby E, a AES / EBU channel can send up to 8channels of high quality digital audio stream, and also can be loaded Dolby digital control data signals (often called the metadata, including the Dolby digital mono mode, dynamic range, type, output level automatic adjustment of parameters, to ensure that users can correct Dolby digital program ). Dolby E with its advanced coding algorithm and higher data transmission rate, can ensure the digital TV audio signals through as many as 10cycle coding - decoding or other editing process, and does not cause quality deterioration. Dolby E audio can be associated with various formats of video signal is a