function b = stdhpf_get(fu, fs) %% y = stdhpf(x, fu, fs) % % Standard high-pass filter % % Input % x - input signal % fu - upper band-edge frequency % fs - sample rate % % Output % y - filtered signal % % Reference AES17 5.2.6 %% % Copyright (c) 2017, 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 % %% Design filter rp = 0.5; rs = -50; % Some margin vs. requirement a = [0 1]; fc = min(1.3*fu, 0.99*fs/2); f = [fu fc]; dev = [ 10^(rs/20) (10^(rp/20)-1)/(10^(rp/20)+1) ]; [n, wn, beta, ftype] = kaiserord(f, a, dev, fs); b = fir1(n, wn, ftype, kaiser(n+1,beta)); if 0 f = linspace(0, fs/2, 1000); h = freqz(b,1, f, fs); figure plot(f, 20*log10(abs(h))) hold on; plot( [0 fu], [-40 -40], 'r', [fc fs/2], [-0.5 -0.5], 'r', [fc fs/2], [0.5 0.5], 'r'); hold off; grid on; end end