L64780 LSI Logic Corporation, L64780 Datasheet - Page 36

• Manufacturer Part Number: L64780
• Description: Dvb-t Cofdm Demodulator Technical Manual 2/00
• Manufacturer: LSI Logic Corporation

The bit deinterleaver rearranges these groups of soft decisions to
separate soft decisions generated from the same carrier. The bit
deinterleaver passes these soft decisions to the output interface of the
L64780 for external decoding.
There are 6-bit deinterleavers, I0 to I5. For QPSK, one COFDM carrier
provides two soft decisions: one from the real part, and one from the
imaginary part. I0 deinterleaves the soft decision extracted from the real
part; I1 deinterleaves the soft decision from the imaginary part. In this
case, I2 to I5 are not used.
For 16 QAM (both hierarchical and nonhierarchical), one COFDM carrier
provides four soft decisions: two from the real part, and two from the
imaginary part. Ten deinterleaves the MSB soft decision extracted from
the real part; I1 deinterleaves the MSB from the imaginary part. I2
deinterleaves the LSB from the real part; I3 deinterleaves the LSB from
the imaginary part. In this case, I4 and I5 are not used.
For 64 QAM (both hierarchical and nonhierarchical), one COFDM carrier
provides six soft decisions: three from the real part, three from the
imaginary part. I0 deinterleaves the MSB soft decision extracted from the
real part; I1 deinterleaves the MSB from the imaginary part. I2
deinterleaves the CSB from the real part; I3 deinterleaves the CSB from
the imaginary part. I4 deinterleaves the LSB from the real part; I5
deinterleaves the LSB from the imaginary part.
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Architectural Overview