106 lines
3.1 KiB
Matlab
106 lines
3.1 KiB
Matlab
function fbr = eq_fir_blob_quant(b, bits)
|
|
|
|
%% Quantize FIR coefficients and return vector with length,
|
|
% out shift, and coefficients to be used in the setup blob.
|
|
%
|
|
% fbr = eq_fir_blob_resp(b, bits)
|
|
% b - FIR coefficients
|
|
% bits - optional number of bits, defaults to 16
|
|
%
|
|
% fbr - vector with length, in shift, out shift, and quantized coefficients
|
|
%
|
|
|
|
%%
|
|
% Copyright (c) 2016, Intel Corporation
|
|
% All rights reserved.
|
|
%
|
|
% Redistribution and use in source and binary forms, with or without
|
|
% modification, are permitted provided that the following conditions are met:
|
|
% * Redistributions of source code must retain the above copyright
|
|
% notice, this list of conditions and the following disclaimer.
|
|
% * Redistributions in binary form must reproduce the above copyright
|
|
% notice, this list of conditions and the following disclaimer in the
|
|
% documentation and/or other materials provided with the distribution.
|
|
% * Neither the name of the Intel Corporation nor the
|
|
% names of its contributors may be used to endorse or promote products
|
|
% derived from this software without specific prior written permission.
|
|
%
|
|
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
% POSSIBILITY OF SUCH DAMAGE.
|
|
%
|
|
% Author: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
|
|
%
|
|
|
|
if nargin < 2
|
|
bits = 16;
|
|
end
|
|
|
|
%% Quantize
|
|
[bq, shift] = eq_fir_quantize(b, bits);
|
|
|
|
%% Check trailing zeros
|
|
nf = length(bq);
|
|
nz = nf;
|
|
while bq(nz) == 0
|
|
nz = nz - 1;
|
|
end
|
|
if nz < nf
|
|
nb = nz + 1;
|
|
fprintf(1,'Note: Filter length was reduced to %d -> %d due to trailing zeros.\n', ...
|
|
nf, nb);
|
|
bq = bq(1:nb);
|
|
else
|
|
nb = nf;
|
|
end
|
|
|
|
%% Make length multiple of four (optimized FIR core)
|
|
mod4 = mod(nb, 4);
|
|
if mod4 > 0
|
|
pad = zeros(1,4-mod4);
|
|
bqp = [bq pad];
|
|
nnew = length(bqp);
|
|
fprintf(1,'Note: Filter length was %d, padded length into %d.\n', nb, nnew);
|
|
else
|
|
nnew = nb;
|
|
bqp = bq;
|
|
end
|
|
|
|
fbr = [nnew shift bqp];
|
|
|
|
end
|
|
|
|
function [bq, shift] = eq_fir_quantize(b, bits)
|
|
|
|
% [bq, shift] = eq_fir_quantize(b, bits)
|
|
%
|
|
% Inputs
|
|
% b - FIR coefficients
|
|
% bits - number bits for 2s complement coefficient
|
|
%
|
|
% Outputs
|
|
% bq - quantized coefficients
|
|
% shift - shift right parameter to apply after FIR computation to
|
|
% compensate for coefficients scaling
|
|
%
|
|
|
|
scale = 2^(bits-1);
|
|
|
|
%% Output shift for coefficients
|
|
m = max(abs(b));
|
|
shift = -ceil(log(m+1/scale)/log(2));
|
|
bsr = b*2^shift;
|
|
|
|
%% Quantize to Q1.bits-1 format, e.g. Q1.15 for 16 bits
|
|
bq = eq_coef_quant(bsr, bits, bits-1);
|
|
|
|
end
|