Next
|
Prev
|
Top
|
JOS Index
|
JOS Pubs
|
JOS Home
|
Search
Window Method for FIR Filter Design
In practical
FFT
processors, we are limited to a
finite duration
impulse response
(
FIR filters
).
An ``obvious'' method for
FIR filter design
is to simply
window
the ideal
impulse
response, just like we window ideal
sinusoids
in
spectrum analysis
:
where
is a
zero centered
window of length
(odd)
We saw that the rectangular window is optimal in the
least-squares
sense, but a poor choice for typical audio
filter design
. What about other windows?
Windowing is
multiplication in the time domain
convolution
in the
frequency domain
.
Thus, in the
window method
, the
ideal
frequency response
is convolved with the window transform:
The convolution `smears' the response, introducing deviations in both the pass-band and stop-band.
Next
|
Prev
|
Top
|
JOS Index
|
JOS Pubs
|
JOS Home
|
Search
[Comment on this page via email]
``
The Window Method for FIR Digital Filter Design}
'', by
Julius O. Smith III
, (From Lecture Overheads,
Music 421
).
Copyright ©
2020-06-27
by
Julius O. Smith III
Center for Computer Research in Music and Acoustics (CCRMA),
Stanford University
[Automatic-links disclaimer]