【正文】 igital audio field laboratory, Dolby not only in the t。 for each license 畢業(yè)設(shè)計（論文）外文資料 9 production of the product prototype ( prototype ) test。 in quantization process, the mantissa is shaking, shaking the pseudo random number generator can be on a different platform to get the same results. By the end of six blocks of the spectral envelope, coarse quantization of the mantissa and the corresponding parameters consisting of AC3 data frame format, continuous frame merged into a digital stream output. By the time domain is transformed to the frequency domain block length selection is the exponential transform coding based on. As defined in AC3two length switching, a512sample value point of the long block, a256sample value point of short block. In the analysis of signal spectrum, to deal with the channel signal blocks cut made longer, so that you can get a better frequency resolution, but also can get higher coding efficiency. But long data block may contain a number of different possible recognition of noise, such as preecho. That is to say the ear due to time and frequency exists on the shadowing effect in the exponential transform coding is a contradiction, not at the same time, must plan as a whole processing. For the steady state signal, whose frequency varies with time transform slow, in order to improve the coding efficiency, requirement filter has good frequency resolution, which requires a long block。t because video interference blind audio, sound burr or other distortion. Dolby E audio and video frames in the sequence are pletely corresponding, can achieve precise audio and video integrated editing. More importantly, by use of this new type of coding technology, the existing radio and television system without largescale transformation can spread multichannel digital TV audio signals, thereby greatly reducing the system cost. Dolby E application is in digital television stations intermediate transfer, from a local television program transmitted by satellite to another local TV station. Dolby E in conveying to the transmitting terminal will be converted to PCM audio, and then encoded into Dolby digital signal, transmitted to thousands of households. Therefore, consumers in the home can be directly received by Dolby E signal, but only receives a digital signal on channel . In order to avoid the confusion, usually Dolby E called transfer coding system, and Dolby will be called to launch digital coding system. Dolby E standard data transfer rate is / sec (20bit / 48kHz for audio signal ), typical operating mode is +2, using six channel transmits a surround sound signal, the other two channel transmission of twochannel matrix coding signal ( such as Dolby ProLogic surround sound ) or dual mono stereo signal. Can also work in other modes, such as with two mono signal+1+1 pattern, three way stereo signal 3x 2 mode and a six single channel signal6x 1 mode. Dolby39。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 pletion, 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. AC3 multichannel frame Dolby 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. 畢業(yè)設(shè)計（論文）外文資料 4 Dolby surround and DTS surround is similar in that they are lossy digital pression technology. This is referred to as emotional data pression 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 techniq ue uses a direction identifying circuit or a directional logic circuit, so that the use of Dolby pany this circuit technology of sound is called Dolby Pro Logic sound。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 Lband X light. In 1961 he received a doctor39。畢業(yè)設(shè)計（論文）外文資料 江西理工大學(xué)應(yīng)用科學(xué)學(xué)院 畢業(yè)設(shè)計 (論文 )外文資料翻譯 系 別： 信息