Depuncture - Xilinx System Generator V2.1 Reference Manual

Xilinx System Generator v2.1 Reference Guide

Depuncture

equals the length of insert string x (the number of ones in the depuncture code) and
produces output data of type UFixK_0 where K equals the length of insert string x
(the length of the depuncture code ).
The Xilinx Depuncture block can be used to decode a range of punctured convolution
codes. The following diagram illustrates an application of this block to implement soft
decision Viterbi decoding of punctured convolution codes.
Figure 3-32: Example of Depuncture block use
The previous diagram shows a matched filter block connected to a serial to parallel
block. The serial to parallel block concatenates two continuous soft inputs and
presents it as a 6-bit word to the depuncture block. The depuncture block inserts the
symbol '100' after the 3-bits from the MSB for code 0 ( [1 0 1] ) and 6-bits from the MSB
for code 1 ( [1 1 0] ) to form a 9-bit word. The output of the depuncture block is
serialized as soft decision 3-bit input words for the Viterbi decoder which decodes the
punctured convolutional code and outputs the decoded data.
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The Xilinx Depuncture block allows you to insert arbitrary symbol into
your input data at the location specified by the depuncture code and
creates a new value. This value is presented as output from the block.
The Xilinx depuncture block accepts data of type UFixN_0 where N
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