Mu Law Quantizer

Illustrates the impact of mu-law companding (compressing and expanding) and quantization of a speech

Speech processing designates a team consisting of Prof. Lawrence Rabiner (Rutgers University and University of California, Santa Barbara), Prof. Ronald Schafer (Stanford University), Kirty Vedula and Siva Yedithi (Rutgers University). This exercise is one of a set of speech processing exercises that are intended to supplement the teaching material in the textbook “Theory and Applications of Digital Speech Processing” by L R Rabiner and R W Schafer.
This exercise quantizes a designated speech file using a mu-law quantizer with a bit rate of nbits per sample, where nbits is typically in the range of 2-10. For the chosen value of nbits, the program plots the quantized and the error signals along with an estimate of the signal and error power spectrum, and a histogram of the error signal values. The program also plays out the error signals in order to get a feeling for how much noise is introduced into the quantized signal at different bit rates.