VooDoo DCR 6000, Planning & Installation Manual

Page: 24 / 149

1. General DCR 6024/6128/6000
1 – 15 Planning and Installation – Rev. 1 / 7. 2001
The DCR 6024/6128/6000 offers a confidence playback facility for video and audio
tape monitoring during record in DTV mode. In data mode, confidence playback is
used to check the recorded data and rewrite if necessary.
Digital recording and playback in conjunction with sophisticated error correction re-
sult in excellent picture and sound quality in DTV mode. Even after 20 tape dubbing
generations there will be no noticeable loss of quality.
The DCR 6024 includes a very powerful error correction facility with a total output
error rate of 10
-11
.
A two step error correction system, based on the Reed Solomon Code is imple-
mented to correct data reading errors.
There are two types of errors:
Single errors
Burst errors
In data mode (DCR 6128) the error correction capabilities are increased once
more. In conjunction with a rewrite function, controlled by the result of confidence
playback functions the corrected bit error rate (BER) will be in the range of 10 E–17.
In both modes the playback quality is checkable by the ”Channel Condition” indica-
tors (LEDs) and/or by the display of the ”ADJUST” menu.
The ”Inner-Code” is used to correct up to 7 single errors in each datablock of 227
bytes (DTV mode) or 230 Bytes in data mode.
With the restriction that the off tape bit error rate is smaller than 10
-4
and no burst
errors occur, the residual error rate after ”Inner correction” will be less than 10
-16
.
This is about one million times better than D-1 format VTR performance.
Due to scratches and tape drop outs, not only single errors but also large burst er-
rors can occur. To overcome this problem the DCR 6024/6128 has a powerful ”Out-
er-Code” too.
Extensive burst errors up to 141 648 bytes of data could be corrected in DTV mode
by ”Outer correction”. That is 25 times more than a D-1 format recorder can.Using
advanced integration techniques the most powerful error correction of existing digi-
tal video standards is implemented in the DCR 6024.
In data mode (DCR 6128) the “Outer correction” is more than twice as powerful
as in DTV mode. In conjunction with the rewrite function during record the corrected
BER will be in the range of 10 E–17.
If the capacity of the error correction system is exceeded by larger defects, an error
concealment function becomes active which covers the defective data.
High quality
recording and
playback
Error Correction
Single error
correction
Burst error
correction
Concealment
(DTV–mode)