基于matlab实现了音乐信号处理中的恒Q变换(Constant Q Transformation).rar

% genlgftkern 7/99 write this in the time domain % write a genkern like genkern.c for a const Q trans (?? genkern was for transform from fft) % % % % Example: [kerncos, kernsin, freqs ] = genlgftkern(174.6141, 1.0293022366 , 11025, 120, 1102); % % nfreqs and windsizmax optional but must input 0 if not a value % will choose 100 ms max and nfreqs up to Nyq % minfreq = 440/(2^(1/12))^16 ; % F3 174.6141 G3 = 195.9977 % nfreqs = 60; % freqrat = 2^(1/12); % 2^(1/24) = 1.0293022366 % SR = 11025 ; % windsizmax = fix(.1 * SR); % take a 100 ms max function [kerncos, kernsin, freqs] = genlgftkern(minfreq, freqrat, SR, nfreqs, windsizmax, winnam, constwind); if (exist('constwind') & constwind ~= 0 ), fprintf('genlgftkern; Calculating kernels with constant windowsiz = %.0f\n', constwind); elseif ~exist('constwind'), constwind = 0; end % Put these steps back in if want to run this prog indep of logftS % if (nargin < 5 | windsizmax == 0) % no input windsizmax %if windsizmax == 0 % windsizmax = floor( .1 * SR); % take a 100 ms max % fprintf('No input maximum window size. Taking 100 ms max.\n'); %end % if (nargin < 4 | nfreqs == 0) % no nfreqs either %if nfreqs == 0 % nfreqs = fix( log(SR/(2*minfreq))/log(freqrat) ); % to give highest freq at the Nyq % fprintf('No input number of freqs; taking freqs from minfreq to Nyquist = %.0f freq bins\n', nfreqs); %end % winnam = 'hamming'; if ~exist('winnam'), winnam = 'hamming'; fprintf('Using default window Hamming\n'); else, fprintf('Input window %s \n', winnam); end if winnam(1:4) == 'rect', winnam = 'boxcar'; end Q = 1/(freqrat - 1); TWOPI = 2*pi; mindigfreq = TWOPI * minfreq / SR; freqs = minfreq * (freqrat .^ [(0:1:nfreqs-1)]); pos = find(freqs < SR/2); freqs = freqs(pos); nfreqs = length(freqs); digfreq = freqs * TWOPI/SR; % shouldn't need the following since fixed up freqs if sum(find(digfreq > pi)) ~= 0, error('freq over Nyq'); end flag = 1; if constwind == 0 windsizOk = fix (TWOPI*Q ./digfreq); % period in samples time Q % arg = (pi/2) * ones(nfreqs, windsiz); windsizmax; windsizOk(1); if (windsizmax > windsizOk(1)), windsizmax = windsizOk(1); flag = 0; end pos = find(windsizOk > windsizmax); % if windsizmax < windsizOk(1) so get some windows not as long as necess for that Q if (flag) fprintf('genlgftkern: Const window %.0f up to freq position %.0f and frequency %.0f out of %.0f frequencies. windsizMinfreq = %.0f Q=%.1f\n', ... windsizmax, max(pos), digfreq(max(pos)) * SR/(2*pi), length(digfreq), windsizOk(1), Q); else fprintf('genlgftkern: No const window; windsizmax = %.0f = windsizMinfreq = %.0f Q=%.1f\n', ... windsizmax, windsizOk(1), Q); end fprintf('\n'); windsizOk(pos) = windsizmax; kerncos = zeros(nfreqs, windsizOk(1) ); kernsin = zeros(nfreqs, windsizOk(1) ); numzeros = windsizOk(1) - windsizOk; numzerosO2 = round(numzeros/2); else kerncos = zeros(nfreqs, constwind ); kernsin = zeros(nfreqs, constwind ); end % Get kaiser number if window is kaiser if length(winnam) > 5 if winnam(1:6) == 'kaiser' if length(winnam) == 7, kaiserno = winnam(7); elseif length(winnam) == 8, kaiserno = winnam(7:8); else, kaiserno = '8'; % default is 8 for no input kaiser number end winnam = 'kaiser'; end end if constwind == 0, for k = 1:nfreqs sz = windsizOk(k); switch(winnam) case 'kaiser' winstr = [ winnam '(' num2str(sz) ',' kaiserno ')']; otherwise winstr = [ winnam '(' num2str(sz) ')']; end % fprintf(' calc window %s \n', winstr); wind = eval(winstr); wind = wind'; % wind = boxcar(windsizOk(k))'; numz = 1; if numzerosO2(k) ~= 0, numz = numzerosO2(k); end; kerncos(k, numz: numz + windsizOk(k)-1) = (1/windsizOk(k)) * ... cos(digfreq(k)*( -sz/2 : sz/2 - 1 )).* wind; % cos(digfreq(k)*(0:windsizOk(k)-1)).* wind; % cos(digfreq(k)*(0:windsizOk(k)-1)).* wind((1:windsizOk(k))); kernsin(k, numz: numz + windsizOk(k)-1) = (1/windsizOk(k)) * ... sin(digfreq(k)*( -sz/2 : sz/2 - 1 )).* wind; % sin(digfreq(k)*(0:windsizOk(k)-1)).* wind; % sin(digfreq(k)*(0:windsizOk(k)-1)).* wind((1:windsizOk(k))); end else for k = 1:nfreqs sz = constwind; switch(winnam) case 'kaiser' winstr = [ winnam '(' num2str(sz) ',' kaiserno ')']; otherwise winstr = [ winnam '(' num2str(sz) ')']; end % fprintf(' calc window %s \n', winstr); wind = eval(winstr); wind = wind'; % wind = boxcar(windsizOk(k))'; kerncos(k, 1 : constwind) = (cos(digfreq(k)*( -constwind/2 : constwind/2 -1 ))).* wind; % kerncos(k, 1 : constwind) = (cos(digfreq(k)*(0:constwind-1))).* wind; % cos(digfreq(k)*(0:windsizOk(k)-1)).* wind((1:windsizOk(k))); kernsin(k, 1 : constwind) = (sin(digfreq(k)*( -constwind/2 : constwind/2 -1 ))).* wind; % kernsin(k, 1:constwind) = (sin(digfreq(k)*(0:constwind-1))).* wind; end end % fprintf('nfreqs = %.0f ; windsizmax = %.0f \n',nfreqs, windsizmax);