Interleaver deinterleaver – Xilinx V2.1 User Manual

Page 55

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Communication

55

Xilinx Blocks

Block Parameters Dialog Box

The Xilinx depuncture block can be configured using its Block Parameters dialog box.

Figure 3-33: Depuncture block parameters dialog box

Parameters specific to the Xilinx Puncture block are:

Depuncture Code

: specifies the depuncture pattern for inserting the string to

the input.

Insert Symbol

: specifies the binary word to be inserted in the depuncture

code.

Other parameters used by this block are described in the Common Parameters section
of the previous chapter.

The Depuncture block does not use a Xilinx LogiCORE.

Interleaver Deinterleaver

The Xilinx Interleaver/Deinterleaver block implements an
interleaver or a deinterleaver. An interleaver is a device that
rearranges the ordering of a sequence of symbols in a one-to-one
deterministic manner. Associated with any interleaver is a
deinterleaver, a device that restores the reordered sequence.

When the block is in interleaver mode, the input data sampled on
the

din

port shall be multiplexed into and out of B shift registers

onto the

dout

port using two (synchronized) commutator arms,

as illustrated in the figure below.

B

is the number of branches as entered in the block’s

parameters dialog. Branch 0 shall have a shift register of zero length. Branch 1 shall
have a shift register of length

L

. Branch 2 shall have a shift register of length

2L

.

Branch (

B-1

) shall have a shift register of length

(B-1)L

.

L

is the branch length

constant entered as an array with a length of one.

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