The question is not clear to me.
You can record a sound signal using ausiorecorder(Fs, NBITS, NCHANS). There you can define the frequency Fs as 8kHz (not "KHz", the lowercase "k" and "z" is important) and NBITS to 8.
If you have recorded your signal as a WAV file with a higher frequency and resolution, explain this in detail.
It is a good idea to perform all the processing in high resolution (DOUBLES!) and convert it to 8 bit afterwards:
x = rand(1, 1000) * 2 - 1;
minx = min(x);
rangex = max(x) - minx;
x8 = uint8(255 * (x - minx) / rangex);
Remember, that your professor is payed for teaching. It would be very efficient and direct, to ask him.
Best Answer