JVC XRCD ~全攻略~ 已陆续加入中文解说 - 非常发烧网

華爺 - 2008/3/29 12:28:00

XRCD (即eXtended Resolution Compact Disc，延伸解析CD之简写)是一种CD的特殊刻板和制造程序，是JVC用来生产高音质红皮书CD的专利技术。首次出现于1995年。

技术性概观
XRCD标准只定义了CD的刻板和制造过程，制造出来的成品CD是完全符合红皮书规格的，也就是说都是16-bit、44.1 kHz取样。这代表XRCD亦完全相容于一般的CD播放器。不同之处在于，从原本的类比或数位来源录音转印至CD上时，JVC使用了进阶的dithering演算法，称作K2技术。

XRCD的价格约是一般CD的两倍到三倍，JVC把此归因于高品质刻板和制造的高成本。 JVC声称，次等的CD刻板技术会让母带的声音降级，他们则努力使用最新的科技来弥补这个损失。

刻板过程
如果声音来源是类比的，首先将使用JVC的专利K2 20位元或24位元ADC将讯号转换成数位资料，然后这些数位资料会被烧录在MO碟片上供运输。

碟片然后送到JVC位于横滨的工厂，此处运用了许多减少jitter的技术。首先数位资料将透过K2 "super-coding"运算，转换成标准的16-bit音讯，最后套用EFM编码。在刻板时，使用高精度的DVD K2雷射加上所谓的"Extended Pit Cut"技术，优化刻制玻璃母带时的「线性速度」（使用极端精确的铷时钟来控制，让每个坑洞的长度足够精确，来消灭jitter失真）。然后玻璃母带直接用于压制CD（一般要再压一道金属母带）。

XRCD2和XRCD24是原始XRCD制造过程的加强版。 XRCD2改用MO碟片来储存K2数字转换器的输出资料；XRCD24则把类比至数位的取样深度提高至24位元。

華爺 - 2008/3/29 12:31:00

K2泛指光碟从录音，混音，母带后期制作，到生产光碟这一连串步骤，所使用的提升音质的软硬体技术。 20bit K2，或者K2 HD，则是专指母带后期制作时，所使用的mastering技术。例如K2独门的dithering，将原始20bit的资料带进CD规格的16bit里，所以称为20bit K2。
然而这种dithering的技术，各家都有，不是只有JVC有，例如SONY也有SBM。所以K2可以说只是不同的mastering理念，会特别强化某些特色，让声音比较突出。
因此，K2不需要特别的解码器来解码，它只是一般普通的msatering系统，做出来的还是一般普通的CD，用一般普通的播放器就可以播放。
虽然说明书上会提到K2 Enocder，K2编码器，但是这只一个耍帅的名词而已，目的是要让你觉得它的技术很高深，但是其实它并不需要一个相对应的Decoder解码器，才能解出它的效果。

華爺 - 2008/3/29 12:33:00

XRCD = Extended Resolution Compact Disc:

XRCD (short for eXtended Resolution Compact Disc) is a special mastering and manufacture process patented by JVC that is used for producing high fidelity redbook Compact Discs. It was first introduced in 1995.

Overview XRCDs are in every aspect regular CDs that just have been manufactured to stringent quality standards. This means that they can be played on any conventional compact disc player. It is interesting to note that an XRCD is supposedly priced about twice as high as a regular full-priced CD. JVC attributes this to the high cost of the quality mastering and manufacturing process.

Mastering process

If digital, the source material is first converted to analogue with a K2 20-bit or 24-bit digital-to-analog converter. The signal is then digitized with JVC's K2 analog-to-digital converters. This musical information is next encoded on a magneto-optical disk for transportation.

The disk is sent to JVC's Yokohama manufacturing plant, where after reducing jitter and distortion the musical signal is down-converted to 16-bit through a K2 "super coding" process. This 16-bit signal is then EFM-encoded before going through a high-precision DVD K2 laser using a proprietary "Extended Pit Cut" technology. This optimizes the linear velocity of the glass master (giving precise pit lengths), as well as eliminating any time jitters, all the while controlled by an extremely accurate Rubidium clock. All CDs are then stamped directly from the glass master.

XRCD2 and XRCD24 are improved versions of the original XRCD process. XRCD2 is the first to record to a magneto-optical disk via the digital K2 regenerator. XRCD24 upgraded the transported music signal's bit width from 20 to 24 bits.

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