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This has to be one of the most off-beat subjects I have seen on TV this year.这必须是最外击败我在电视上看到，今年的项目之一。 There I was watching Discovery on a cold Japan winters day, while others were out trying to photograph something for the next Photo Hunt competition, when a program started and explained the birth of the Compact Disc.在那里，我看着在寒冷的冬天一天，日本发现，而另一些则是从试图在未来摄影亨特的竞争，当一个程序开始，解释了光盘的诞生拍摄的东西。

So the story goes that it became a 74-minute medium because the then-president of Sony, Norio Ohga, wanted to be able to hear all of Beethoven's 9th symphony,a popular piece in Japan, without interruption.因此，据说，它成为74分钟的媒体，因为当时的索尼公司，大贺典雄先生，希望能够听到贝多芬的第九交响曲，在日本广为一块没有中断，一切。 I would venture to say that I can totally believe this story as I have been in enough Japanese meetings to understand how irrational some of the requirements can be, so this is not an extreme requirement at all.我冒昧地说，我完全可以相信这是我在日本举行了足够的了解如何不合理的一些要求可以，所以这根本不是一个极端的要求故事。

However, having watched intently I began to question the validity of all this so I decided to turn to everybody's friend, Google, and I uncovered an但是，在专注地看着我开始怀疑这一切的有效性，所以我决定把大家的朋友，谷歌，我发现一个 article文章 which I found very interest. ，我觉得很感兴趣。

Apparently, the story regarding the Sony President's desires was not the case at all, at least not according to an engineer who worked on the CD.显然，故事就索尼总裁的愿望并非在所有情况下，至少不是根据谁的工程师在CD工作。 Instead it was Philips, not Sony, who were pushing, and they were pushing for the CD to be close in size to the “compact cassette tape”.相反，它是飞利浦，而不是索尼，谁是推，而他们为推动裁谈会的规模接近“小型盒式磁带”。 Now, it turns out that a CD is slightly wider than that—120mm instead of 115mm, but the basic premise holds.现在，事实证明，一个CD略高于更广泛，12公分，而不是115毫米，但基本前提成立。

Also in the article it explains why CDs are 16 bit and 44.1khz.另外，在文章中解释了为什么光盘是16位和44.1kHz的。 Not as arbitrary as we are usually told.不是任意的，我们通常说。 The BBC in the UK was one of the first to adopt digital sound, and they were working with a 13-bit distribution system for the transmitter network, sampled at 32 kHz.在英国，英国广播公司是率先采用数字声音之一，他们与一个13位的发射机网络分销系统在32 kHz的采样，工作。 Stockham's experiments in 1972-3 with the Soundstream system involved sample rates averaging around 40 kHz, and he used computer tape as the means of storage, which made it practical to store data at 16 bit resolution because of the byte-orientated nature of computer data storage.在1972-3斯托克姆的实验与Soundstream制度所涉及的采样率平均约40千赫，他作为贮存的方法，这使得它的实际存放在16个字节，因为位分辨率的计算机数据导向性的数据，计算机磁带存储。 8 bits would have been too few, and 14 bits would have meant inefficient use of the storage space, so 16 bits seemed logical. 8位将是太少了，和14位，就意味着对存储空间的使用效率，使16位似乎合乎逻辑。

Sony and Philips worked under the following constraints:索尼和飞利浦合作在以下限制：

• The bits to be etched the CD had to be 0.83 microns long and 1.6 microns apart.该位是蚀刻裁谈不得不0.83微米和1.6微米分开。 Hence about 750,000 bits fit in 1 sq. mm因此，大约750,000位适合1平方毫米
• CD uses 16-bit audio with 2 (stereo) channels. CD使用2 16位音频（立体声）通道。
• Sound is sampled at at 44.1 KHz for声音的采样为44.1千赫 historical reasons由于历史的原因 . 。 So 1 sq mm translates to about 750,000 bits / 44,100 Hz / 32 = 0.53 seconds of music.因此，1平方毫米转化为约75位/ 44,100赫兹/ 32 = 0.53秒的音乐。

To read the full story select要阅读全文选择 this link此链接 . 。

This story clearly is not as sexy or as cult-of-personality as the “这个故事显然是没有性感或的邪教，个性的“ We did it for the Pres 我们做的介绍 ， 它 ” version but eminently interesting in its own right. “版本，但显然其本身有趣。

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This post is tagged这个职位是标签 Why does the Compact Disc hold 74 minutes为什么光盘举行74分钟