www.gusucode.com > dsp 案例源码程序 matlab代码 > dsp/CompareFixedpointFloatingPointExample.m

    %% Compare Fixed-point Output with Floating-Point Output
% Construct a Lowpass Filter
h = dfilt.dffir(firgr(27,[0 .4 .6 1],... 
[1 1 0 0]));             	
%%
% Set h to use fixed-point arithmetic to filter.
% Quantize the coeffs.
h.arithmetic = 'fixed'; 
%%
% Cast h to double-precision 
hd = double(h);       
%%
% Set up an input signal.    			                         			 
n = 0:99; x = sin(0.7*pi*n(:)); 
%%
% Fixed-point output.
y = filter(h,x);     
%%
% Floating-point output.
yd = filter(hd,x);            
%%
% Compare the Fixed-point output with Floating-point output
FixedFloatNormDiff=norm(yd-double(y),inf)