%% Area Reduction of Filter Subsystem
% To reduce the number of multipliers in the HDL implementation of a multifilter
% design, use the *SharingFactor* HDL Coder(TM) optimization.  
open_system('DiscreteFIRSharing')
%%
% The model includes a sinusoidal signal source feeding a filter subsystem 
% targeted for HDL code generation.
%
% <<../DiscreteFIRSharing_SubSystem.png>>
% 
% The subsystem contains a Discrete FIR Filter block and a Biquad Filter 
% block. This design demonstrates how the optimization tools share resources 
% between multiple filter blocks. 
%%
% The Discrete FIR Filter block has 43 symmetric coefficients. The Biquad 
% Filter block has 6 coefficients, two of which are unity. With no optimizations
% enabled, the generated HDL code takes advantage of symmetry and unity 
% coefficients. The nonoptimized HDL implementation of the subsystem uses 
% 27 multipliers. 
%
% <<../DiscreteFIRSharing_NoOptims.png>>
%
% To enable streaming optimization for the *Multi-Filter Subsystem*,
% right-click the subsystem and select *HDL Code* > *HDL Block Properties*. 
%
% <<../DiscreteFIRSharing_HDLBlkProps.png>>
%
% Set the *SharingFactor* to 27 to reduce the design to a single multiplier.
% The optimization tools attempt to share multipliers with matching data 
% types. To reduce to a single multiplier, you must set the internal data 
% types of the filter blocks to match each other.
%% 
% To observe the effect of the optimization, under *Configuration Parameters* 
% > *HDL Code Generation*, select *Generate resource utilization report* and
% *Generate optimization report*. Then, to generate HDL code, right-click the 
% Multi-Filter Subsystem and select *HDL Code* > *Generate HDL for Subsystem*.
%%
% With the *SharingFactor* applied, the subsystem upsamples the rate by 27
% to share a single multiplier for all the coefficients. 
%
% <<../DiscreteFIRSharing_Arch.png>>
%
% In the *Code Generation Report* window, click *High-level Resource
% Report*. The generated HDL code now uses one multiplier. 
%
% <<../DiscreteFIRSharing_Resource.png>>
%


%% 
% Copyright 2012 The MathWorks, Inc.