If an audio signal is to be coded, either for compression or for digital transmission, it must undergo some form of quantization. Most often, a general technique known as vector quantization is employed for this task, but this technique must be tailored to the specific application so it will not be addressed here. In this assignment, we will observe the effect of uniformly quantizing the samples of two audio signals. a) Record your voice for 4 seconds and play it again using predefined MATLAB audio functions.
b) Use your Uquant function to quantize each of these signals to 7, 4, 2 and 1 bits/sample.
c) Listen to the original and quantized signals and answer the following questions using the comments in the same MATLAB file:
1- For each signal, describe the change in quality as the number of b/sample is reduced?
2- For each signal, is there a point at which the signal quality deteriorates drastically?
3- At what point (if any) does it become incomprehensible?
4- Which signal's quality deteriorates faster as the number of levels decreases?
5. Do you think 4 b/sample is acceptable for telephone systems? ... 2 b/sample?
d) Use subplot to plot in the same figure, the four quantized speech signals over the index range 7201:7400.