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从CD向DVD光存储发展的关键技术 总被引:1,自引:0,他引:1
1998年国际光存储技术从CD存储向高密数字DVD存储发展最关键的一年,国外称之为DVD革命。为此,着重论述了从CD向DVD光盘发展的关键技术,包括DVD-只读,DVD-可录,DVD-可随机重写等各类光盘的关键技术及相应生产线的技术升级。 相似文献
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从1996年年底开始,以DVD影碟机为先锋的各类DVD产品纷纷走入市场,DVD因而成为世界瞩目的数字技术焦点。为此,本文拟就DVD的有关问题向大家作一介绍。图11、DVD的含义及类型对DVD这个名词,大家都不陌生。最初,它是作为LD(LaserDis... 相似文献
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日本松下公司新近推出最小的DVD播放器DVD-L50掌上剧院(DVD-L50PalmTheater),可以作为便携式DVD播放器在旅行时使用,也可以作为家庭影院系统的一部分与其它设备集成在一起使用。DVD-L50是松下公司去年推出的DVD-L10的升... 相似文献
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正当国内DVD影碟机在视听市场进行激烈竞争之际,国际新一代音频格式的DVDAudio(以下简称DVDA)和SuperAudioCD(以下简称SACD)已脱颖而出,这两种代表“未来音响”的音频媒体,将动摇近20年来一直作为HiFi音源的CD主导地位,特别是DVDA又让人们强烈地意识到它与视频之间的关系,使音响界又多了不少持币观望者。DVDA和SACD各有什么特点?它们的现状与发展前景又怎样?这是音响爱好者议论较多的话题,笔者就此作一些分析和探讨。DVDAudio的技术特点1999年2月,DVD联盟指导委员会通过了该联… 相似文献
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一年多前的国际音响大展上超级音频CD SACD和DVD-Audio就放声高歌,基本标准1.0版本也已敲定,按说应该在音响发烧友的期望中很快上市。 无论是SACD还是DVD-Audio碟片的物理格式和数据处理部分都与DVD-Video相当,价格绝对不是问题。特别是DVD—Audio设计时满口承诺可以被DVD-Video下兼容。后期出品的DVD-Video不少已把DVD-Audio标准中的多种格式编程在内,当然前题是播放没有加密的DVD-Audio碟片。还音基本设备已经有了,可碟片呢?除了少量试音碟或… 相似文献
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介绍一款24bit/96kHz的多轨数码录音机随着DVD的大量流行,DVDAudio势必成为未来音频“CD”产品的新格式。一些专业录音师和拥有个人录音室的朋友都希望拥有一套能录制DVDAudio质量的多轨数字录音系统,能够快速、方便、高品质地完成录音工作。何谓DVDAudio的质量DVDAudio“CD”的音质是令人着迷的,那究竟何谓DVD Audio的质量呢?我们知道,凡是数码音响都有一个模拟/数字(A/D);数字/模拟(D/A)的转换过程,数字音频的质量有很大部分与A/D、D/A的转换质量有… 相似文献
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目前,DVD碟片的销量已超过了录像带,正成为新世纪记录媒体的主力。在这种情况下,对DVD碟片的统一要求和质量品质的认定就提到了议事日程上来。DVD碟片测试认证服务的公司也开始向外提供服务。另外,AV设备和DVD光驱的品质规格测试用碟片也已于 1997年上市,以保证设备的品质和互换性能得到严格的比测。 现在DVD正迅速地从现行单面4.7CB容量品种向20GB超级高密度品种发展。CD的新品种DDCD(倍密度CD)也已登场。DVD品种也进入基本稳定状态,现将其主要规格特性和标准版本适用范围汇集如下。 1… 相似文献
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测量低信噪比电压的数字相敏解调算法及性能分析 总被引:13,自引:0,他引:13
本文研究了低信噪比正弦电压幅值及相位测量用的数字相敏解调(DPSD)算法,给出了DPSD算法的主要参数(数据长度、取样频率、A/D转换器位数)与低信噪比电压测量的性能指标(测量精度、频率分辨力、动态储备及最小可测电压)之间的关系。对纳伏电压的实际测量表明,理论分析与测量结果是一致的。本文研究结果可以用于数字式相敏解调程序的设计及应用 相似文献
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An efficient algorithm is presented for conversion of spectral density, the measure of signal purity commonly used in the design process, to another popular measure, Allan variance. Curves are presented that show the relationship between parameters controlling the degree of approximation and the resulting inaccuracy. A flow chart of the algorithm is given. Execution times for a sample problem are compared with times using simpler algorithms 相似文献
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Wakai K. Moribe N. Nasu Y. Ikeda H. Li J. 《IEEE transactions on instrumentation and measurement》1990,39(6):910-913
A method for measuring AM (amplitude modulation) signal distortion caused by AM to PM (phase modulation) conversion at the output of an AM radio transmitter is presented. A novel type of measuring instrument is also presented for testing the phase distortion which may occur in an AM radio transmitter when an AM modulation signal is applied. The down-converted AM signal is first divided into the inphase and orthogonal-phase components, and these signals are processed by an operational circuit to obtain phase distortion, which is the angle between the orthogonal-phase and inphase components. A phase angle of 10° or more is detected in the prototype version 相似文献
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针对参考信号波形难以构造等情况,提出一种利用期望源信号听觉特征进行信号盲提取的方法,根据源信号的听觉特征先验知识,将提取信号与期望信号听觉特征向量的接近程度作为度量,使用非线性最小二乘法进行迭代计算分离向量,提取出与期望信号在听觉特征上最为接近的源信号。对这种方法进行了理论推导,并使用不同类型的信号进行了仿真。仿真结果表明,该方法具有良好的效果,且由于仅利用了信号的听觉特征,而不需要参考信号的具体波形,对于不同类型的信号,具有广泛的适应性,具有良好的应用价值。 相似文献
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In this paper, a procedure to measure impedances using data-acquisition boards and genetic algorithms is developed. This approach to impedance measurements has the advantage of being low cost. The multiharmonic acquired waveforms are characterized using a genetic algorithm that finds the frequency of the signal, which, in turn, is used in a multiple linear least-squares (LS) waveform-fitting algorithm. The magnitude and phase of the unknown impedance can then be evaluated. A multiharmonic signal is used so that the frequency dependence of the impedance can be obtained from a single measurement. The measurement results are validated by measurements made with an impedance analyzer. The main advantage of the genetic algorithm over traditional search methods is its robustness to convergence problems. 相似文献
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The effects of channel estimation errors on the channel capacity of a discrete time, discrete input, infinite output Rayleigh fading channel are investigated. The case of conventional modulation methods such as phase shift keying (PSK) and quatrature amplitude modulation (QAM) is investigated at first where it was observed that the capacity degrades rapidly with increasing channel estimation errors. The effect of error in the channel estimation is similar to the effect of higher noise in the channel that depends on the transmitted signal. A genetic algorithm is used to optimise the signal constellation in order to maximise the capacity for a given finite number of signal points. The aim of trying to maximise the capacity is to estimate the remaining gap in performance between a traditional modulation scheme such as QAM and the best possible constellation that is optimised for the channel. The constellations obtained from the genetic algorithm are, in general, not directly implementable. A method to design practical robust signal constellations that overcome the effect of channel state information (CSI) error is presented. The robust signal constellations obtained show a performance that is very close to the optimal constellations. In this work, the probability distribution of the error in CSI is assumed to be known. 相似文献