18
DVX
Instruction
Manual
Disc Grading System
This feature provides a means of instantly evaluating a disc without looking at the individual data. There are five
different grades covering a wide range of performance: A, B, C, D, and F. Here are the criteria used to determine the
GRADE. These criteria are somewhat arbitrary, but reflect generally accepted practice in the industry.
CD Discs
GRADE A =
AVE BLER over the whole disc not greater than 5.0
PK BLER not greater than 100
PK E12 not greater than 400
NO E22 ERRORS
NO E32 ERRORS
GRADE B =
AVE BLER over the whole disc not greater than 50.0
NO E22 ERRORS
NO E32 ERRORS
GRADE C =
AVE BLER over the whole disc not greater than 100.0
NO E32 ERRORS
REF less than 60%
I
11
/ I
top
less than 0.6
I
3
/ I
top
less than 0.3
I
3
/ I
top
greater than 0.7
MAX BETA greater than 15%
MIN BETA less than -10%
GRADE D =
AVE BLER in all ten second periods is less than 220
E32 greater than 0 on Audio disc
GRADE F =
AVE BLER in any ten second period is greater than 220
TOT E32 greater than 1000 on Audio disc
TOT E32 greater than 0 on data disc
REF less than 48%
I
11
/ I
top
less than 0.48
I
3
/ I
top
less than 0.24
I
3
/ I
top
greater than 0.84
MAX BETA greater than 20%
MIN BETA less than -15%
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 demanding uses.
Most data 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. The only grade that is
unacceptable is F, since this disc does not meet Red Book specifications. Still, this disc may be usable, and the data
fully recoverable.
Uncorrectable errors (E32) may not be a problem on audio discs, since the player’s interpolation circuitry will hide
these errors. Some players can interpolate over up to eight consecutive bad samples, although the sound quality may be
compromised.
Uncorrectable errors do not necessarily make a data disc unusable either. Errors that are uncorrectable in the main
CIRC correction stage may still be corrected by the EDC/ECC sector level error correction used on most data discs.
Therefore, the data may still be recoverable, and can still verify if you are comparing to the original. Of course a disc
like this has no tolerance for additional degradation, such as scratches and fingerprints, so access time will increase and
it will soon fail.
Since there is no Red Book specification for uncorrectable errors (E32), a GRADE D disc is still considered within Red
Book specifications. data disc’s however, should have no E22 or E32 errors, as made. If the BLER exceeds 220 in any
ten-second period, the disc is outside the Red Book specifications. Grade F discs do not meet Red Book specs, and
therefore should be rejected.
Содержание DVX-4
Страница 1: ...D DV VX X 4 4 DVD CD ANALYZER OPERATING MANUAL Version 3 1 TM...
Страница 2: ...COPYRIGHT 2005 2012 CLOVER SYSTEMS ALL RIGHTS RESERVED...
Страница 43: ...Fig 23 CD HF Eye Pattern DVX Instruction Manual 35...
Страница 57: ...Fig 28 CD Error Test with QuickScan Fig 29 CD Error Test without QuickScan DVX Instruction Manual 49...
Страница 58: ...Fig 30 DVD Error Test without QuickScan Fig 31 DVD Error Test with QuickScan 50 DVX Instruction Manual...
