17-06-2003
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#1 (permalink)
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| CDFreaks Resident
Join Date: May 2002 Location: Sthlm
Posts: 5,497
| Disc Grading System - BLER
BLER
BLER - BLock Error Rate. A measure of the integrity of the data refrieved from a compact disc.
The block error rate can be measured over a given period of time.
It is usually reported in two or three ways by analyzers, i.e. :
Average BLER over entire part of the disc that has been read, peak BLER, etc.
Average of 220 is considered a marketable disc according to Red Book and Yellow Book standards.
Most manufacturers set higher standards for themselves, striving for an average BLER of under 50.
BLER
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Disc Grading System
There are five different grades covering a wide range of performance: A, B, C, D, and F.
This feature provides a means of instantly evaluating a disc without looking at the individual data.
Here are the criteria used to determine the GRADE.
These criteria are somewhat arbitrary, but reflect generally accepted practice in the industry.
GRADE A = AVE BLER over the whole disc less than 6
NO E22 ERRORS
NO E32 ERRORS
GRADE B = AVE BLER over the whole disc less than 51
NO E22 ERRORS
NO E32 ERRORS
GRADE C = AVE BLER over the whole disc less than 101
NO E32 ERRORS
LESS THAN 1000 DROPOUTS
GRADE D = AVE BLER in all ten second periods is less than 220
GRADE F = AVE BLER in any ten second period is greater than 220 or Track Loss
occurred.
Generally, a GRADE A disc represents the best possible quality of disc.
GRADE B is still an excellent disc, but not quite perfect.
GRADES A & B are good discs for any use, including the most stringent CD-ROM uses.
Most CD-ROM publishers do not like to see BLER more than 50 or any E22 or E32
errors. Therefore, GRADES C through F would be unacceptable for these users.
However, GRADES C through D are still usable discs.
Source > Clover QA-201 or QA-201 Instruction Manual |
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