Aliased Tune
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Download the starter code for this lab and unzip it.
Also, install the lib6003 library if you have not already done so.
Instructions are available here.
The starter code contains a file called tune.py. In that file, there is a
description of a tune in the form of a list. Each entry in the list is a tuple
of (frequency, duration), where frequency is the frequency of a note (in
Hz) and duration is the length of that note (in seconds).
Add code to tune.py to synthesize a WAV file for this tune by concatenating
together a sequence of discretized pure sine waves of the given frequencies and
durations. Use a sampling rate of 44.1kHz. Note that there should only be a
single sine wave playing at any given point in time in the resulting WAV file.
Note that you can use the
lib6003.audio.wav_write function
to save the file as a WAV file.
After you have saved the file, play it back. Do you recognize the tune?
Next, generate two new lists of (frequency, duration) tuples that play
the same tune when using a sampling rate of 44.1kHz. Your first list should
only include continuous frequencies in the range (22050Hz, 44100Hz]. Your
second list should only include continuous frequencies in the range (44100Hz,
66150Hz].
All three files should sound identical when played at 44100Hz.
Please enter your new lists below.
Then upload your modified tune.py file, which should contain not only three
lists of (frequency,duration) tuples but also code to create each of the three WAV files.
Please describe your approach to each of the parts of this lab.
(frequency, duration) pairs containing
only frequencies in the range (22050Hz, 44100Hz] into the box below.
(frequency, duration) pairs containing
only frequencies in the range (44100Hz, 66150Hz] into the box below.
tune.py file. Your updated file should include your code for generating WAV files from the given lists of tuples.