Digital Signal Processing
Dr. Fred J. Taylor, Professor
Lesson Title: Windows Challenge
Challenge: [10]
Challenge Problem
A rectangular pulse, given by:
[
]
∈
=
otherwise
k
if
k
x
0
]
10
,
0
[
1
is to be analyzed using a 31point DFT.
The magnitude frequency response of the signal is
studied using a 31sample data record and the data record windowed using a 13sample
Blackman window.
Any change out to 10% in the two spectra will be considered notable, and
changes greater than 10% to be significant.
Q:
Predict the effect of windowing on peak to sideband gain,
Response
The signal being transformed, with or without windowing, is not periodic but the FFT will treat it
as such.
One would expect that since the points of symmetry of the 31sample signal x[k] and
window w[k] are so dissimilar, that the outcomes will be quit different significantly (different).
Another way of looking at it, the signal nonzero samples are clustered about the initial end
point of the 31sample data record.
The window coefficients are small (nearzero) over this
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Summer '09
 yang
 Digital Signal Processing, Frequency, Signal Processing, Blackman, magnitude frequency response, rectangular windowed signal

Click to edit the document details