IF_hilbert.m

function [ XPhase,f,Imag,t,f_OGZ,maxf_emdvalue ]=IF_hilbert(x,fs)
%x is the signal that will be analysised
%fs is sample frequency
%XPhase is instanepus phase
%f is instaneous phase
%t is the time string
%f_OGZ is the mean frequency
%maxf_emdvalue is the frequency whose property is maximum.

if length(x)<2
    error('The length of x is too short')
end
Ts=1/fs;
x=hilbert(x);
XPhase=phase(x);
for n=1:length(x)
    t(n)=n*Ts;
    Imag(n)=abs(x(n));
    if n==1
        f(n)=1/2/pi*(XPhase(2)-XPhase(1))/Ts;
    elseif n==length(x)
        f(n)=1/2/pi*(XPhase(n)-XPhase(n-1))/Ts;
    else
        f(n)=1/2/pi*(XPhase(n+1)-XPhase(n-1))/2/Ts;
    end
end
f_OGZ=sum(f)/length(f);
f_range=0:1:100;
f_pro=hist(f,f_range);
maxf_emd_pro=max(f_pro);
maxf_emd_pro_index=find(f_pro==maxf_emd_pro);
maxf_emdvalue=f_range(maxf_emd_pro_index);
end