41 lines
602 B
Mathematica
41 lines
602 B
Mathematica
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% lspwarp.m
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% David Rowe Sep 2012
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%
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% Experimenting with non-linear LSP frequency axis for LSP quantisation
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% Plots a scaled mel axis.
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1;
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function mel = freq2mel(f)
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mel = 70*log10(1 + f/700);
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endfunction
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function freq = mel2freq(m)
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freq = 700*(10 ^ (m/70) - 1);
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endfunction
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x = []; y = [];
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for freq = 100:25:4000
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mel = freq2mel(freq);
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x = [x freq];
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y = [y mel];
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end
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plot(x,y)
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grid
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mel_start = floor(freq2mel(100));
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mel_end = floor(freq2mel(4000));
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x = []; y = [];
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for mel=mel_start:mel_end
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freq = mel2freq(mel);
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x = [x freq];
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y = [y mel];
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end
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hold on;
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plot(x,y, '+')
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hold off;
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