由相位噪声曲线计算积分相噪和Jitter的方法

先放一张忘了从哪扒下来的图：

基本思路：
分段求积分相噪，相加得整体的积分相噪，进而得到以弧度为单位的相位抖动，最终转换为以时间为单位的Jitter。

MATLAB代码：

function ph2jt(fc, f, ph)
    % ph2jt(fc, f, ph) 
    % fc - carrier frequency 
    % f - offset frequency 
    % ph - phase noise at offset frequency 
    N = length(f); 
    if(ph(1) > 0) 
        for i=1:N 
            ph(i) = -ph(i); 
        end 
    end 
    a = zeros(1, N-1); 
    a_dBc = zeros(1, N-1); 
    jt = zeros(1, N-1); 
    for i=2:N 
        f0 = f(i-1); 
        f1 = f(i); 
        ph0= 10^(ph(i-1)/10); 
        ph1= 10^(ph(i)/10); 
        k = 10*log10(ph1/ph0)/log10(f1/f0); 
        a(i-1) = 10*f1*ph0*(f1/f0)^(k/10)/(10+k) - 10*f0*ph0/(10+k); 
        a_dBc(i-1) = 10*log10(a(i-1)); 
        jt(i-1) = sqrt(2*a(i-1))/(2*pi*fc); 
    end 
    a_tol = sum(a); 
    a_tol_dBc = 10*log10(a_tol); 
    jt_tol = sqrt(2*a_tol)/(2*pi*fc); 
    for i=1:N-1 
        display(sprintf('%g ~ %g\t%g\t%f\t%g', f(i), f(i+1), a(i), a_dBc(i), jt(i))); 
    end 

    display(sprintf('Total\t\t%g\t%f\t%g', a_tol, a_tol_dBc, jt_tol));