GDC21D003 Datasheet, PDF (64/77 Pages) Hynix Semiconductor – VSB Receiver

6.6.5 Convolutional Deinterleaver
Convolutional deinterleaver performs the opposite
function of the transmitter convolutional
interleaver. Even strong NTSC co-channel signals
passing through the NTSC rejection filter and
creation of short bursts due to NTSC vertical edges
GDC21D003
are reliably handled due to the interleaving and RS
coding process. The deinterleaver uses Data Field
Sync for synchronizing with the first data byte of
the data field. The structure is shown in Figure
6.6.6. The deinterleaver can be bypassed for
performance tests by setting I²C register64[5]
(Deint_on) to ‘0’.
1
(B-1)M
From
Symbol-to-Byte
Converter
2
(B-2)M
2M
50
51
M (=4 Bytes)
To
Reed-Solomon
Decoder
(B=)52
M=4, B=52, N=208, R-S Block = 207,B¡ ¿M=N
Figure 6.6.6 Convolutional Deinterleaver
6.6.6 Reed-Solomon Decoder
Reed-Solomon decoder can correct up to 10-
byte errors per Data Segment that is encoded by
RS(207, 187) code. Any burst errors created by
impulse noise, NTSC co-channel interference, or
Viterbi decoding errors, are greatly reduced by the
combination of the convolutional deinterleaving
and RS error correction. The RS decoder can be
turned off for performance test by setting the I²C
register64[4](rsdec_on) to ‘0’. The number of
segment errors per one second is written in I²C
register65 and register67 so that they can be read
through I²C register control. The encoder
polynomial is as follows. The coefficients of the
polynomial are defined in Galois field GF(256).
G(X) = X²⁰ + 152X¹⁹ + 185X¹⁸ + 240X¹⁷ + 5X¹⁶ + 111X¹⁵ + 99X¹⁴ + 6 X¹³ + 220X¹² + 112X¹¹
+ 150X¹⁰ + 69X⁹ + 36 X⁸ + 187 X⁷ + 22X⁶ + 228X⁵ + 198X⁴ + 121X³ + 121X² + 165X¹ + 174
65