93 lines
1.7 KiB
Matlab
Executable File
93 lines
1.7 KiB
Matlab
Executable File
function eval_blit()
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sinc_use_lut = 0
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L = 96000;
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fs = 48000;
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fstart = 440;
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fend = 440;
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df = (fend-fstart)/L
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# for saw
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rho = 0.95;
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nhw = 4096;
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Hw = kaiser(nhw, 8)';
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max_m = fix((fs/fstart/2.0)) + 1
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sinc_table_calc = sinc_use_lut;
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if sinc_table_calc == 1
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nharm = max_m
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nsin = 1024;
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xx = (0:nsin)/nsin - 0.5;
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mmm=0;
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for mm=1:nharm,
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mmm=mmm+1;
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bb(mm, :) = sin(mmm*xx*pi);
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end;
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aa = sin(xx*pi);
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end;
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x = 0.5;
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z = -1;
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f = fstart;
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sqr = 0.0;
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saw = 0.0;
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tri = 0.0;
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a = 1;
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b = 1;
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for n = 1:L,
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if x >= 0.5,
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x = x - 1;
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p = fs/f;
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fraq = 1.0/p;
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m = fix((p/2.0)) + 1;
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z = -z;
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end;
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if sinc_use_lut == 1
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nn = (x+0.5)*nsin + 1;
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ni = fix(nn);
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nf = nn - ni;
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bbi = (bb(m, ni+1) - bb(m, ni))*nf + bb(m, ni); % Fractional delay (linear interpolation)
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aai = (aa(ni+1) - aa(ni))*nf + aa(ni); % Fractional delay (linear interpolation)
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if (aai ~= 0)
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blit = fraq* bbi / aai * Hw(fix((x+0.5)*nhw)+1);
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else
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blit = fraq;
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end
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else
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b = sin(m*x*pi);
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a = sin(x*pi);
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if (a ~= 0)
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blit = fraq * b/a * Hw(fix((x+0.5)*nhw)+1);
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else
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blit = fraq;
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end
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end
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saw = rho*saw + (fraq - blit);
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sqr = sqr + z*blit;
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tri = tri + 2*(sqr-0.5)*fraq;
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vtri(n) = tri;
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vsaw(n) = saw;
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vsqr(n) = 2*(sqr - 0.5);
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vblit(n) = blit;
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x = x + fraq;
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f = f + df;
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end;
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close all
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figure;
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plot(1:L, vsaw, 1:L, vblit); grid;
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wavwrite(0.5*vtri, fs, 'tri.wav');
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wavwrite(0.5*vsqr, fs, 'sqr.wav');
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wavwrite(0.5*vsaw, fs, 'saw.wav');
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wavwrite(0.5*vblit, fs, 'blit.wav');
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