diff options
Diffstat (limited to 'macros/stft.sci')
| -rw-r--r-- | macros/stft.sci | 206 |
1 files changed, 128 insertions, 78 deletions
diff --git a/macros/stft.sci b/macros/stft.sci index 7c30360..1d4b462 100644 --- a/macros/stft.sci +++ b/macros/stft.sci @@ -1,89 +1,139 @@ -function [y,c]= stft(x, varargin) -//Compute the short-time Fourier transform of the vector X -//Calling Sequence -//Y = stft (X) -//Y = stft (X, WIN_SIZE) -//Y = stft (X, WIN_SIZE, INC) -//Y = stft (X, WIN_SIZE, INC, NUM_COEF) -//Y = stft (X, WIN_SIZE, INC, NUM_COEF, WIN_TYPE) -//[Y,C] = stft (X) -//[Y,C] = stft (X, WIN_SIZE) -//[Y,C] = stft (X, WIN_SIZE, INC) -//[Y,C] = stft (X, WIN_SIZE, INC, NUM_COEF) -//[Y,C] = stft (X, WIN_SIZE, INC, NUM_COEF, WIN_TYPE) -//Parameters -//X: Real scalar or vector -//WIN_SIZE: Size of the window used -//INC: Increment -//WIN_TYPE: Type of window -//Description -//Compute the short-time Fourier transform of the vector X with NUM_COEF coefficients by applying a window of WIN_SIZE data points and an increment of INC points. -// +function [y, c] = stft(x, win_size, inc, num_coef, win_type) +//Compute the short-time Fourier transform of the vector X. +//Calling Sequence: +//y = stft(x) +//y = stft(x, win_size) +//y = stft(x, win_size, inc) +//y = stft(x, win_size, inc, num_coef) +//y = stft(x, win_size, inc, num_coef, win_type) +//[y, c] = stft(x) +//[y, c] = stft(x, win_size) +//[y, c] = stft(x, win_size, inc) +//[y, c] = stft(x, win_size, inc, num_coef) +//[y, c] = stft(x, win_size, inc, num_coef, win_type) +//Parameters: +//x: Real scalar or vector +//win_size: Size of the window used +//inc: Increment +//num_coef: Coefficients of Fourier transform +//win_type: Type of window +//Description: +//Compute the short-time Fourier transform of the vector X with num_coef coefficients by applying a window of win_size data points and an increment of inc points. //Before computing the Fourier transform, one of the following windows is applied: -// //"hanning" -> win_type = 1 -// //"hamming" -> win_type = 2 -// //"rectangle" -> win_type = 3 -// -//The window names can be passed as strings or by the WIN_TYPE number. -// -//The following defaults are used for unspecified arguments:WIN_SIZE= 80, INC = 24, NUM_COEF = 64, and WIN_TYPE = 1. -// -//Y = stft (X, ...)' returns the absolute values of the Fourier coefficients according to the NUM_COEF positive frequencies. -// -//'[Y, C] = stft (x, ...)' returns the entire STFT-matrix Y and a 3-element vector C containing the window size, increment, and window type, which is needed by the 'synthesis' function. +//The window names can be passed as strings or by the win_type number. +//The following defaults are used for unspecified arguments: win_sizse = 80, inc = 24, num_coef = 64, and win_type = 1. +//y = stft(x, ...)' returns the absolute values of the Fourier coefficients according to the NUM_COEF positive frequencies. +//'[y, c] = stft (x, ...)' returns the entire stft-matrix y and a 3-element vector c containing the window size, increment, and window type, +//which is needed by the 'synthesis' function. +//Examples: +//[y, c] = stft([1; -2; -5]) +//y = [] +//c = [80, 24, 1] + + funcprot(0); + rhs = argn(2); + if (rhs < 1 | rhs > 5) + error("Wrong number of input arguments."); + end + if (~isvector (x)) + error ("stft: X must be a vector"); + end + + if (rhs == 1) + win_size = 80; + inc = 24; + num_coef = 64; + win_type = 1; + elseif (rhs == 2) + inc = 24; + num_coef = 64; + win_type = 1; + elseif (rhs == 3) + num_coef = 64; + win_type = 1; + elseif (rhs == 4) + win_type = 1; + end + + if (type(win_type) == 10) + switch (convstr(win_type, 'l')) + case "hanning" , win_type = 1; + case "hamming" , win_type = 2; + case "rectangle" , win_type = 3; + otherwise + error ("stft: unknown window type"); + end + end -funcprot(0); -lhs= argn(1); -rhs= argn(2); + x = x(:); -if(rhs <1 | rhs>5) - error("Wrong number of input arguments"); -end + ncoef = 2 * num_coef; + if (win_size > ncoef) + win_size = ncoef; + printf ("stft: window size adjusted to %f\n", win_size); + end + num_win = fix ((size(x, 'r') - win_size) / inc); -if(lhs<1 | lhs>2) - error("Wrong number of output arguments"); -end + switch (win_type) + case 1 , win_coef = (window('hn', win_size))'; + case 2 , win_coef = (window('hm', win_size))'; + case 3 , win_coef = ones (win_size, 1); + end + + z = zeros (ncoef, num_win + 1); + start = 1; + for i = 0:num_win + z(1:win_size, i+1) = x(start:start+win_size-1) .* win_coef; + start = start + inc; + end + + y = fft(z, -1, find(size(z) ~= 1, 1)); + + if (nargout() == 1) + y = abs(y(1:num_coef, :)); + else + c = [win_size, inc, win_type]; + end -select(rhs) - case 1 then - select(lhs) - case 1 then - y= callOctave("stft", x); - case 2 then - [y,c]= callOctave("stft", x); - end - case 2 then - select(lhs) - case 1 then - y= callOctave("stft", x,varargin(1)); - case 2 then - [y,c]= callOctave("stft", x, varargin(1)); - end - case 3 then - select(lhs) - case 1 then - y= callOctave("stft", x,varargin(1), varargin(2)); - case 2 then - [y,c]= callOctave("stft", x,varargin(1), varargin(2)); - end - case 4 then - select(lhs) - case 1 then - y= callOctave("stft", x,varargin(1), varargin(2), varargin(3)); - case 2 then - [y,c]= callOctave("stft", x,varargin(1), varargin(2), varargin(3)); - end - case 5 then - select(lhs) - case 1 then - y= callOctave("stft", x,varargin(1), varargin(2), varargin(3), varargin(4)); - case 2 then - [y,c]= callOctave("stft", x,varargin(1), varargin(2), varargin(3), varargin(4)); - end -end endfunction +//input validation: +//assert_checkerror("stft()", "Wrong number of input arguments."); +//assert_checkerror("stft(1, 2, 3, 4, 5, 6)", "Wrong number of input arguments."); +//assert_checkerror("stft([1 2; 3 4])", "stft: X must be a vector"); +//s = "square"; +//assert_checkerror("stft([1 2 3], 8, 4, 6, s)", "stft: unknown window type"); + +//tests: +//assert_checkequal(stft([1 2 3]), stft([1 21 3], 80, 24, 64, 1)); +//assert_checkequal(stft([1 2 3], 80), stft([1 21 3], 80, 24, 64, 1)); +//assert_checkequal(stft([1 2 3], 80, 24), stft([1 21 3], 80, 24, 64, 1)); +//assert_checkequal(stft([1 2 3], 80, 24, 64), stft([1 21 3], 80, 24, 64, 1)); + +//[y, c] = stft([1; -2; -5]); +//assert_checkequal(y, []); +//assert_checkequal(c, [80, 24, 1]); + +//y = stft([1 21 3], 3, 2, 2); +//assert_checkequal(y, [21; 21]); + +//[y, c] = stft([1 21 3], 3, 2, 2); +//assert_checkequal(y, [21; -21*%i; -21; 21*%i]); +//assert_checkequal(c, [3 2 1]); + +//y = stft([1, 3-2*%i, -6-7*%i], 3, 2, 3); +//assert_checkalmostequal(y, [3.60555; 3.60555; 3.60555], 0.5*10^-5); + +//[y c] = stft([1; 3-2*%i; -6-7*%i], 3, 2, 3); +//assert_checkalmostequal(y, [3-2*%i; -0.2321-3.5981*%i; -3.2321-1.5981*%i; -3+2*%i; 0.2321+3.5981*%i; 3.2321+1.5981*%i], 5*10^-4); +//assert_checkequal(c, [3 2 1]); + +//[y c] = stft([1; 3-2*%i; -1-2*%i], 3, 2, 3, 3); +//assert_checkalmostequal(y, [3-4*%i; -0.4641-1.7321*%i; 0-1.4641*%i; -3; 5.4641*%i; 6.4641+1.7321*%i], 5*10^-4); +//assert_checkequal(c, [3 2 3]); +//y = stft([3*%i; 4*%i; -5*%i], 3, 2, 3, 1); +//assert_checkequal(y, [4; 4; 4]); |