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Diffstat (limited to 'macros/shanwavf.sci')
| -rw-r--r-- | macros/shanwavf.sci | 65 |
1 files changed, 37 insertions, 28 deletions
diff --git a/macros/shanwavf.sci b/macros/shanwavf.sci index a597214..e088f60 100644 --- a/macros/shanwavf.sci +++ b/macros/shanwavf.sci @@ -1,30 +1,39 @@ +/*Description + Compute the Complex Shannon wavelet. + The complex Shannon wavelet is defined by a bandwidth parameter fb, a wavelet center frequency fc, and the expression + psi(x) = f * b^{1/2}sinc(fb . x) e^{2 pi i f c x} + on an n-point regular grid in the interval of lb to ub. +Calling Sequence + [psi, x]= shanwavf(lb, ub, n, fb, fc) +Input Parameters + lb, ub (Real valued scalers) : Interval endpoints lb ≤ ub, specified as a pair of real-valued scalars. + n (Real valued integer strictly positive)` : Number of regularly spaced points in the interval [lb,ub], specified as a positive integer. + fb : Time-decay parameter of the wavelet (bandwidth in the frequency domain). Must be a positive scalar. + fc : Center frequency of the complex Shannon wavelet, specified as a positive scalar. +Output Parameters + psi : Complex Shannon wavelet evaluated on the n point regular grid x in the interval [lb,ub], returned as a 1-by-n vector. + x : Grid where the complex Shannon wavelet is evaluated, returned as a 1-by-n vector. The sample points are evenly distributed between lb and ub. +Examples + 1.[a,b]=shanwavf (2,8,3,1,6) + a = [-3.8982e-17 + 1.1457e-31i 3.8982e-17 - 8.4040e-31i -3.8982e-17 + 4.5829e-31i] + b = [2 5 8] */ function [psi,x]=shanwavf(lb,ub,n,fb,fc) - -// Complex Shannon Wavelet -// Calling Sequence -// [psi,x]=shanwavf(lb,ub,n,fb,fc) -// Parameters -// lb: Real or complex valued vector or matrix -// ub: Real or complex valued vector or matrix -// n: Real valued integer strictly positive -// fb: Real or complex valued vector or matrix, strictly positive value for scalar input -// fc: Real or complex valued vector or matrix, strictly positive value for scalar input -// Description -// This is an Octave function -// This function implements the complex Shannon wavelet function and returns the value obtained. The complex Shannon wavelet is defined by a bandwidth parameter FB, a wavelet center frequency FC on an N point regular grid in the interval [LB,UB]. -// Examples -// 1. [a,b]=shanwavf (2,8,3,1,6) -// a = [-3.8982e-17 + 1.1457e-31i 3.8982e-17 - 8.4040e-31i -3.8982e-17 + 4.5829e-31i] -// b = [2 5 8] -// 2. [a,b]=shanwavf(1,2,1,[2,2;i,2],[-1,2;-i,i]) -// a = [-5.5128e-17 - 2.7005e-32i -5.5128e-17 + 5.4010e-32i; -// 8.6404e+06 + 8.6404e+06i -1.9225e-22 - 0.0000e+00i] -// b = 2 - -funcprot(0); -rhs=argn(2); -if (rhs~=5) then - error ("Wrong number of input arguments.") -else [psi,x]=callOctave("shanwavf",lb,ub,n,fb,fc) -end + funcprot(0); + rhs=argn(2); + if (rhs~=5) then + error ("Wrong number of input arguments.") + else + if (n <= 0 || floor(n) ~= n) + error("n must be an integer strictly positive"); + elseif (fc <= 0 || fb <= 0) + error("fc and fb must be strictly positive"); + end + x = linspace(lb,ub,n); + sincx=x; + for i=1:n + sincx(i)=sin(fb*x(i)*%pi)/(fb*x(i)*%pi); + end + psi = (fb.^0.5).*(sincx.*exp(2.*%i.*%pi.*fc.*x)); + end endfunction + |