LC72717PW

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21

Error Correction

(1) Error Correction and Output Conditions of Error-corrected Data (in the default state)

The received data is subject to error detection by the layer 2 CRC and error correction by the (272,190) code for each

one block (272 bits). At the end of correction, preparation for transmission to CPU is made and the INT signal is output.

This is called “horizontal correction”.

In the default state, this INT signal is output only when the output data concerned meets all of three conditions as

follows:

Data whose error correction is completed and for which layer 2 CRC detects no error

Data received during block and frame synchronizations

Data in the data packet

*Depending on the register mode setting, horizontally-corrected data may be output regardless of conditions of  to 

above.

When horizontal correction cannot cover completely, correction by the product code is made frame by frame. For data

that cannot be horizontally corrected, the second horizontal correction is made.

This series of operations is called “vertical correction”. Conditions for the data obtained from vertically-corrected

output are as follows in the default state:

Data that cannot be corrected by horizontal correction, but that has been completely corrected by the vertical

correction

Data in the data packet

Accordingly, horizontally-corrected data is not output. Packet data that cannot be corrected horizontally or vertically

is not output. The parity packet data after vertical correction is not output either.

Vertical correction is applied to the whole packet data that have been received during frame synchronization, and is

executed when horizontal correction cannot correct all packet (block) data. Vertical correction is not made when the

error-free data is received for one frame or when the received data is not synchronous in flame synchronization during

reception. For the packet whose error has been corrected by horizontal correction and any error-free packet, vertical

correction is not made to prevent faulty correction.

In the default setting, the applicable vertically-corrected output is not output when vertical correction has not been

made.

* Depending on the register mode setting, the vertically-corrected data may be output regardless of whether or not

vertical correction is to be made.