Xilinx V2.1 - Manual (Page 58)

58 Xilinx Development System
Xilinx System Generator v2.1 Reference Guide
The Core datasheet can be found on your local disk at:
%XILINX%\coregen\ip\xilinx\eip1\com\xilinx\ip\sid_v1_1\doc\sid
.pdf
This is a licensed core, available for purchase on the Xilinx web site at:
http://www.xilinx.com/ipcenter/interleaver
Puncture
The Xilinx Puncture block allows you to remove arbitrary bits specified
as a puncture code from your input data and create a new value. This
value is presented as the output from the block. The Xilinx puncture
block accepts data of type
UFixN_0 (where N is equal to the length of
the puncture code) and outputs data of type UFixK_0 (where K is equal to the
number of ones in the puncture code).
The Xilinx Puncture block can be used to implement a range of punctured
convolution codes. The following diagram illustrates an application of this block.
Figure 3-37: Example of a Puncture block application
The preceding diagram shows a 1/2 rate Convolutional Encoder block connected to a
binary input signal source. The slice blocks separate the convolution code output over
the two branches. The output of the slice block is connected to a Serial to Parallel
block which concatenates the output of the convolution code to form a 3-bit word. The
puncture block removes the center bit for code 0 ( [1 0 1] ) and LSB bit for code 1
( [1 1 0 ] ) to produce a 2-bit punctured output which is again serialized to be
connected to the I and Q channel for baseband shaping.