Apply a digital filter (direct form II transposed): Difference between revisions
Apply a digital filter (direct form II transposed) (view source)
Revision as of 17:58, 9 November 2019
, 4 years ago→{{header|MATLAB}}
Line 540:
-0.21172192, -0.17474556, 0.06925841, 0.38544587, 0.65177084
</pre>
=={{header|Lua}}==
{{trans|C++}}
<lang lua>function filter(b,a,input)
local out = {}
for i=1,table.getn(input) do
local tmp = 0
local j = 0
out[i] = 0
for j=1,table.getn(b) do
if i - j < 0 then
--continue
else
tmp = tmp + b[j] * input[i - j + 1]
end
end
for j=2,table.getn(a) do
if i - j < 0 then
--continue
else
tmp = tmp - a[j] * out[i - j + 1]
end
end
tmp = tmp / a[1]
out[i] = tmp
end
return out
end
function main()
local sig = {
-0.917843918645, 0.141984778794, 1.20536903482, 0.190286794412,-0.662370894973,
-1.00700480494, -0.404707073677, 0.800482325044, 0.743500089861, 1.01090520172,
0.741527555207, 0.277841675195, 0.400833448236,-0.2085993586, -0.172842103641,
-0.134316096293, 0.0259303398477,0.490105989562, 0.549391221511, 0.9047198589
}
--Constants for a Butterworth filter (order 3, low pass)
local a = {1.00000000, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17}
local b = {0.16666667, 0.5, 0.5, 0.16666667}
local result = filter(b,a,sig)
for i=1,table.getn(result) do
io.write(result[i] .. ", ")
end
print()
return nil
end
main()</lang>
{{out}}
<pre>-0.15297398950031, -0.43525782905022, -0.13604339698849, 0.69750332654796, 0.65644469246903, -0.43548245325611, -1.0892394611529, -0.53767654956275, 0.51704999231321, 1.0522497471554, 0.96185430037364, 0.6956900940096, 0.42435629509553, 0.19626223182179, -0.027835124463393, -0.21172191545012, -0.17474556222276, 0.069258408901195, 0.38544587430744, 0.65177083881931,</pre>
=={{header|MATLAB}}==
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