% quant_demo.m
% Demonstration of uniformly quantizing speech with various numbers of levels.
% 
% ELEC 470, Spring 1998, R. Kozick

% Load speech signal

% Choose number of bits R to set L = 2^R quantization levels

R = 7;
L = 2^R;

s = auread('/home/pleiades/ACM/snd/clint_eastwood.au');

% Normalize amplitudes to range [+0.5, -0.5]

s = s/max(s)*0.5;

% Perform the quantization

sq = round(s*L)/L;

% Play the original

sound(s)

% Play the quantized version

sound(sq)
fprintf('Quantized with R = %d bits = %d levels\n', R, L);
fprintf('Signal-to-quantization-noise ratio = %f dB\n', 1.8 + 6*R);