Waveform Quantization and Compression - Digital Signal Processing: Fundamentals and Applications - page 540

%

sez ¼ b(1)*dq(1);
for i ¼ 2:6
sez ¼ sez þ b(i)*dq(i);
end
se ¼ a(1)*sr(1) þ a(2)*sr(2) þ sez;
d ¼ sl - se;

%
% Perform quantization
%

dqq ¼ log10(abs(d))/log10(2.0)-y;

ik 0;

for i

¼

1:7
if dqq > qtable(i)
ik ¼ i;
end
end
if d < 0
ik ¼ -ik;
end
ii(k) ¼ ik;
yu ¼ (31.0/32.0)*y þ witable(abs(ik) þ 1)/32.0;
if yu > 10.0
yu ¼ 10.0;
end
if yu < 1.06
yu ¼ 1.06;
end
yl ¼ (63.0/64.0)*yl þ yu/64.0;

¼

%
%Inverse quantization
%

if ik ¼¼ 0

dqq ¼ 2^(-y);

else
dqq ¼ 2^(invqtable(abs(ik)) þ y);

end
if ik < 0
dqq ¼ -dqq;
end
srr ¼ se þ dqq;
dqsez ¼ srr þ sez-se;

%
% Update state
%
pk1 ¼ dqsez;
%
% Obtain adaptive predictor coefficients