| Sectors
and ECC |
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Super
Audio CD |
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Sector format,
error correction and channel modulation (cont.)
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Error
correction (ECC block)
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Thanks
to the development of new ECC decoding algorithms,
SACD error correction coding using a Reed-Solomon
Product Code can be applied
across
a larger amount
of data with better error correction capabilities.
This reduces error correction
redundancy to
approximatively 13% or half that of CD.
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After
EDC calculation over the Data Sectors, scrambling
data are added to the 2048 bytes of Main Data
in the Data Sector. Then, the Error Correction Code
is applied over 16 Data Sectors, or one ECC block
(33,024 bytes)
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After
putting the data bytes in a matrix of 192 rows * 172
columns, 16 bytes of PO-parity are added to each
column. Next, 10 bytes of PI-parity are added to
each of the 208 rows (192 data + 16 formed by the
PO-bytes) to form a Reed-Solomon Product Code with
208 rows and 182 columns (172 data + 10 formed by
the PI-bytes).
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ECC
block : Product Code RS(208,192,17)*RS(182,172,11)
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This
code can correct at least 5 byte errors in each row
and at least 8 byte errors in each column. By
applying several alternating calculations over rows
and columns, much bigger error patterns can be
solved.
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Recording
Sector
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Finally,
the PO-rows are interleaved with the data rows in a
regular order (12 data, 1 PO) and each interleaved
ECC block is divided into 16 Recording Sectors. In
this way, a Recording Sector contains the original
data from 1 Data Sector + 12*10 PI-bytes + 1 row of
182 PO-bytes, together 2366 bytes.
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Recording
Sectors
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