mirror of https://github.com/thesofproject/sof.git
69 lines
2.6 KiB
Matlab
69 lines
2.6 KiB
Matlab
function [y, mark]= sync_chirp(fs, direction)
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%% [y, mark]= sync_chirp(fs, direction)
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%
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% Returns a chirp signal that can be used to mark end and beginning of audio
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% tests to synchronize input and captured output accurately.
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%
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% Input
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% fs - sample rate
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% direction - direction of frequency sweep 'up' or 'down'
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%
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% Output
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% y - windowed chirp signal
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% mark - struct with parameters for chirp
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%
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%%
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% Copyright (c) 2017, 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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mark.a_db = -10;
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mark.a = 10^(mark.a_db/20);
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mark.fs = fs;
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mark.t = 0.2; % Short, to not consume much test time
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switch lower(direction)
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case 'up'
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mark.f0 = 200; % Should work with any speaker
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mark.f1 = 3500; % Should work with any speaker
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case 'down'
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mark.f1 = 200; % Should work with any speaker
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mark.f0 = 3500; % Should work with any speaker
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otherwise
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error('Parameter direction must be ''up'' or ''down''');
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end
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mark.n = round(mark.t*fs);
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t_vec = (0:mark.n-1)/fs;
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w = hanning(mark.n);
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x = chirp(t_vec, mark.f0, mark.t, mark.f1, 'linear')';
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y = x .* w * mark.a;
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end
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