90 lines
2.8 KiB
Mathematica
90 lines
2.8 KiB
Mathematica
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function fbr = eq_fir_blob_quant(b, bits)
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%% Quantize FIR coefficients and return vector with length,
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% out shift, and coefficients to be used in the setup blob.
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%
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% fbr = eq_fir_blob_resp(b, bits)
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% b - FIR coefficients
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% bits - optional number of bits, defaults to 16
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%
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% fbr - vector with length, in shift, out shift, and quantized coefficients
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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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if nargin < 2
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bits = 16;
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end
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[bq, shift] = eq_fir_quantize(b, bits);
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nb = length(bq);
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mod4 = mod(nb, 4);
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if mod4 > 0
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pad = zeros(1,4-mod4);
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bqp = [bq pad];
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nnew = length(bqp);
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fprintf(1,'Note: Filter length was %d, padded length into %d,\n', nb, nnew);
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else
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nnew = nb;
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bqp = bq;
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end
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fbr = [nnew shift bqp];
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end
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function [bq, shift] = eq_fir_quantize(b, bits)
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% [bq, shift] = eq_fir_quantize(b, bits)
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%
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% Inputs
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% b - FIR coefficients
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% bits - number bits for 2s complement coefficient
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%
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% Outputs
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% bq - quantized coefficients
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% shift - shift right parameter to apply after FIR computation to
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% compensate for coefficients scaling
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%
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scale = 2^(bits-1);
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%% Output shift for coefficients
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m = max(abs(b));
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shift = -ceil(log(m+1/scale)/log(2));
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bsr = b*2^shift;
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%% Quantize to Q1.bits-1 format, e.g. Q1.15 for 16 bits
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bq = eq_coef_quant(bsr, bits, bits-1);
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end
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