Using FDATool in Digital Filter Applications
A demo included in the System Generator demos library also shows an efficient way to implement a MAC-based interpolation filter. To see the demo, type the following in the
MATLAB command window:
>> demo blockset xilinx then select FIR filtering: Polyphase 1:8 filter using SRL16Es from the list of demo designs.
Design Overview
This design uses the random number source block from the DSP Blockset library to drive two different implementations of a FIR filter:
•
The first filter is the one that could be implemented in a Xilinx device. It is a fixedpoint FIR filter implemented with a dual-port Block memory and a single multiplyaccumulator.
•
The second filter is what is referred to as reference filter. It is a double-precision, direct-form II transpose filter.
The frequency response of each filter is then plotted in a transfer function scope.
Open and Generate the Coefficients for this FIR Filter
1.
From the MATLAB console window, cd into the directory
<sysgen_tree>/sysgen/examples/mac_fir
.
2.
Open the design model by typing mac_df2t from your MATLAB command window.
For the purpose of this tutorial, the variables coef, coef_width, coef_binpt, data_width
, data_binpt and Fs are not defined. You will first use these variables as mask parameters to the MAC Based FIR block and then design and assign the filter
System Generator for DSP User Guide
UG640 (v11.4) December 2, 2009 www.xilinx.com
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