ELEC 0547 Project #3 Fall 1999
This project will give you some experience with the concept of interpolation by investigating various interpolation schemes and their effects on the interpolated signal.
Exercises
. What is the Nyquist rate for
this signal? Generate a sequence 
that is a sampled version
of 
with a sampling period 
and a length of 1024.
function
seqexp(x,L) that implements the expand operation defined in Eq. 4.84
in the text. The function should take a sequence of length N and expand
it by a factor L to yield a sequence of length L*N. Expand 
to
by a factor of 4.
a and b that represent
this difference equation for the filter command.
filter
that the output 
is a zero-order hold version of 
.
To inspect this visually, you may want to plot only the first 20 or
so points of the input and output sequences.
to 
. Plot the frequency response
of the zero-order hold filter using
freqz,
and use this to explain the relationship between
and 
.
b = 4*
fir1
(81,1/4);, and let a=1. Use these definitions of
a and b in
filter.
Repeat Steps 4 and
5 for this filter. Note: The processing may require more
time for this filter.
To do the following exercises, you may need to save the sequence to a sound file using auwrite or wavwrite and then play the sound on the PC.
sound
to listen to signals 
, 
, and the three versions of
. Describe and explain what you hear.
fan =
auread
('/opt/demo/audio/fanfare.au');
Listen to the original, the expanded, and the three interpolated
signals with L=4. Describe and explain what you hear.
Write a short report describing your findings. The report should contain a concise description of your results. Include listings of your function. Be sure to answer all questions. You are not expected to include in the report all plots which you were required to do; instead, you should summarize in your report the salient features of the unincluded plots.