Lab 6: Smooth Signal

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Task Outline

Due Date: Friday, November 1, 2019
Total Points: 10
Implement a Python program that smoothes an audio signal by averaging a list of integers.

An audio signal is sometimes stored as a list of integer values. The values represent the intensity of the signal at successive time intervals. Of course, in a program, the signal is represented with a list.
Often, a small amount of noise is included in the signal. Noise is usually small, momentary changes in the signal level. An example is the static that is heard in addition to the signal in AM radio.
Smoothing a signal removes some of the noise, and improves the perceptual quality of the signal. This assignment requires you to smooth the values in a list of integers.

First, you should create a result list called smooth, which has exactly the same size as the audio list. Recall that the multiplication operator can be used to create a list which is initialized with zeroes:

smooth = [0] * len(audio)

The first element of the smooth list is a special case, because it should be calculated from the average of the first two elements of the audio list.
The last element of the smooth list is also a special case, because it should be calculated from the average of the last two elments of the audio list.
The internal elements of the smooth list can be calculated from a for loop in the following manner. First, you will need to determine the boundaries of this loop. You should probably begin at index 1, and go up to index len(audio)-1. Recall that the for loop has the following variation:

for i in range(start, stop):

This means that the loop will begin at start, and go up to(but not include) stop.
Then, you will need to calculate the average of three elements in the audio list, for every index i. In other words, you will need to calculate the average of the three values: audio[i-1], audio[i], and audio[i+1].

Description	File Size	File Name
`Python` Source Code for Smooth Signal	1.8KB	lab06.zip

Contents of lab06.zip:

Lab06SmoothSignal/
├── smoothsignal.py
└── testsmoothsignal.py

Write a Python program in the file smoothsignal.py that smoothes an audio signal by averaging a list of integers.
You will write your solution in a function called levelling(audio) right below the place where it says: YOUR CODE HERE
When the function call levelling([1, 5, 4, 5, 7, 6, 8, 6, 5, 4, 5, 4]) is executed, the output of the program should be: [3 3 4 5 6 7 6 6 5 4 4 4 ]

Run the file testsmoothsignal.py to execute the PyUnit test bench. PyUnit indicates a successful test with an OK output, and an unsuccessful test with a FAIL output.