62 lines
2.2 KiB
Matlab
62 lines
2.2 KiB
Matlab
%% xq = dither_and_quantize(x, bits)
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%
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% Input
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% x - input signal
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% bits - number of bits
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%
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% Output
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% (int32) xq - scaled, dithered and quantized signal
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%
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%%
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% Copyright (c) 2016, Intel Corporation
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% All rights reserved.
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%
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% Redistribution and use in source and binary forms, with or without
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% modification, are permitted provided that the following conditions are met:
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% * Redistributions of source code must retain the above copyright
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% notice, this list of conditions and the following disclaimer.
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% * Redistributions in binary form must reproduce the above copyright
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% notice, this list of conditions and the following disclaimer in the
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% documentation and/or other materials provided with the distribution.
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% * Neither the name of the Intel Corporation nor the
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% names of its contributors may be used to endorse or promote products
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% derived from this software without specific prior written permission.
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%
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% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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% POSSIBILITY OF SUCH DAMAGE.
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%
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% Author: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
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%
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function xq = dither_and_quantize(x, bits)
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if (bits > 32) || (bits < 1)
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error('This function supports max 32 bits quantization!');
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end
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scale = 2^(bits-1);
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smax = scale-1;
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smin = -scale;
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sx = size(x);
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nx = sx(1);
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nch = sx(2);
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xq = int32(floor( scale*x + randn(nx,nch) - randn(nx,nch) -0.5)); % TPDF dither
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%xq = int32(round( scale*x )); % Omit dither
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idx = find(xq > smax);
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xq(idx) = smax;
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idx = find(xq < smin);
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xq(idx) = smin;
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end
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