保存度那個我忘了在哪看到的

剛剛又蒐了一下Jitter相關文章
我的認知是jitter(時基誤差)=失真度
也就是jitter=o時(當然實務上是不可能=0)~達到1:1無失真(最正確)
jitter大時~data會讀取錯誤~波模糊無法達到精確bit access
jitter和data/audio都有關
以上

反正這些值都當參考就好~要說公平精準難
都越低越好就沒錯啦

各位大大有沒發現：
如果同時使用Ｓ級的空片
同樣使用ＰＸ－７１６ＳＡ燒錄
－Ｒ的JITTER遠比＋Ｒ低？？

甚至使用Ｐ牌１１０Ｄ燒ＴＹＧ０３（誘電－Ｒ　１６Ｘ）
　　　　Ｂ牌１６４０燒ＹＵＤＥＮ　Ｔ０３（誘電＋Ｒ　１６Ｘ）
一樣用８Ｘ或１６Ｘ燒
－Ｒ的表現都比＋Ｒ好（在jitter方面)

可行的方法去弄一台716A
可測JITTER/BETA

-R jitter<8%
+R jitter<9%

Plextor在CDRinfo的測試本來就是DVD-R燒錄品質較好的.....

That's DVD+R我是測出來最低的是Yuden000T01，
T02、T03都比T01高....= =
T01用1620 test可以低到7%...T02、T03就...8~9%左右

不過DVD+RW Alliance所允許的DVD Jitter是比DVD Forum的高...

Benq也可以測Jitter...

PX-716A我比較想要的是Ta test啊.......XD

Kula2大哪天又想賣716A記得通知小弟...(茶
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另外，A09燒的DVD-R DVD Jitter也不低喔...= =

主要是日本都賣-R吧!!
隨便一家店都是-R佔70% DVD-RAM 20% +R 10%

沒記錯的話
全世界DVD+/-R的銷售量是差不多的.....

此外，MKM、Ricoh染料大廠是屬DVD+RW Alliance陣營
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一直不用DVD-R當主力是DVD-R的ECC比DVD+R差....

有興趣看很多人轉過的這篇
http://www.cdfreaks.com/article/113

裡面有提到
Another bad side effect of this pre-pits method is that DVD-R(W) mastering is made more difficult than with DVD+R(W), since a higher precision is required to cut both the grooves and the pre-pits between them. Special dual-beam recorders are usually required for - stamper mastering, although some manufacturers now also use single beam cutting.

Not only are the pre-pits more error prone than phase modulation, but data they carry are also less protected. In one ECC block pre-pits carry 192 bits of information (one pre-pit block). Out of these 192 bits, 48 are not protected by any error correction mechanism, 24 bits are protected by 24 bits of parity (A parity), and the last 56 bits are also protected by 24 bits of parity (B parity). All in all, this strange heterogeneous structure finally gives a pretty weak protection to the information bits carried by pre-pits.

轉貼的第二段裡面提到DVD-R1個ECC Block裡面有48bits是完全沒有在ECC的保護之下的
此外，在有24bits只有parity保護(A parity)，最後還有56bits只有parity保護(B parity)
意思就是DVD-R的一個ECC Block裡面有48bits完全沒有ECC保護，有80bits(24+556)則是用Partity的保護措施
剩下的才有完全ECC保護.....

Partity是什麼保護措施小弟不是很清楚，有查到的是這個
http://www.iazone.net/article.php3?...03724&mode=flat