Waveform Quantization and Compression - Digital Signal Processing: Fundamentals and Applications - page 543

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;
%
% Inverse quantization
%

ik ¼ ii(k);

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;
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;
out(k) ¼ srr;

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

if tr ¼¼ 1

a ¼ zeros(1,2);

b ¼ zeros(1,6);

0;
td ¼ 0; % Set for the time being
else
% Update predictor poles
% Update a2 first
a2p ¼ (127.0/128.0)*a(2);
if abs(a(1)) < ¼ 0.5
fa1 ¼ 4.0*a(1);
else
fa1 ¼ 2.0*sgn(a(1));
end

tr ¼