annotate arrows/dsp/amelspec.m @ 6:0ce3c2070089
Removed duplicate code and fixed doc in timed_action.
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samer |
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Mon, 14 Jan 2013 14:33:37 +0000 |
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672052bd81f8 |
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beb8a3f4a345 |
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line source |
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1 % amelspec - arrow from audio to log mel spectra
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2 %
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3 % amelspec ::
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4 % N:natural ~'size of FFT used to compute spectra',
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5 % M:natural ~'number of mel bands to compute'
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6 % nonneg ~'sampling frequency',
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7 % options {
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8 % windowfn :: N:natural->[[N]] / @hanning ~'window function';
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9 % lowf :: nonneg / 100 ~'filter bank low frequency in Hz'
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10 % }
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11 % -> arrow( {[[dftbins(N)]]}, {[[L]]}, empty).
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12 %
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13 % Uses antialiased triangular filterbank from lowf to fs/2.
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14
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15 function o=amelspec(N,M,fs,varargin)
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16 opts=prefs('windowfn',@hanning,'lowf',100,'floor',5e-9,varargin{:});
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17 melW = lin2mel(N,fs,[opts.lowf,fs/2],M);
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18 noise_floor=opts.floor;
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19 o = apowspec(opts.windowfn(N))*arr(@cc);
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20 function y=cc(x), y=log(melW*x+noise_floor); end
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21 end
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