matlab taylorwin(n,nbar,sll)加窗函数 c/c++实现 奇数阶

Matlab代码：

function w = taylorwin(n, nbar, sll)
% TAYLORWIN  Computes the Taylor window coefficient vector.
%   W = TAYLORWIN(N, NBAR, SLL) computes the N-point Taylor window
%   with a sidelobe level attenuation of SLL dB and a null-to-null
%   bandwidth of NBAR points.
%
%   Example:
%       w = taylorwin(31, 6, 60);
%       stem(w);
%
%   See also CHEBWIN, KAISER, RECTWIN, WINDOW.

if mod(n, 2) == 0
    error('N must be odd');
end

% Convert sidelobe level from dB to linear scale
A = 10^(sll/(-20));

% Compute beta parameter
if A <= 21
    beta = 0;
elseif A <= 50
    beta = 0.5842 * (A-21)^0.4 + 0.07886 * (A-21);
else
    beta = 0.1102 * (A-8.7);
end

% Compute window coefficients
w = zeros(n, 1);
for i = 0:(n-1)/2
    a = i - (n-1)/2;
    w(i+1) = besseli(0, beta*sqrt(1-(a/nbar)^2))/besseli(0, beta);
    w(n-i) = w(i+1);
end

end

C/C++代码：

#include <math.h>

void taylorwin(int n, int nbar, double sll, double *w)
{
    int i;
    double A, beta, a;

    if (n % 2 == 0) {
        return; /* N must be odd */
    }

    /* Convert sidelobe level from dB to linear scale */
    A = pow(10, sll/(-20.0));

    /* Compute beta parameter */
    if (A <= 21) {
        beta = 0;
    } else if (A <= 50) {
        beta = 0.5842 * pow((A-21), 0.4) + 0.07886 * (A-21);
    } else {
        beta = 0.1102 * (A-8.7);
    }

    /* Compute window coefficients */
    for (i = 0; i <= (n-1)/2; i++) {
        a = i - (n-1)/2;
        w[i] = j0(beta * sqrt(1 - pow(a/nbar, 2))) / j0(beta);
        w[n-i-1] = w[i];
    }
}

注意：在C/C++代码中，需要包含`math.h`头文件，并使用`j0()`函数计算第一类零阶贝塞尔函数的值。