How to get a frequency vector in NUFFT MATLAB CODE?

The example is

t = [0:300 500.5:700.5];

S = 2*sin(0.1*pi*t) + sin(0.02*pi*t);

X = S + rand(size(t));

Y = nufft(X,t);

n = length(t);

f = (0:n-1)/n;

plot(f,abs(Y))

The frequency range here is [0,1],

My question is, for a noun-uniform (unknown) signal, How to calculate the frequency range? It is still 'f = (0:n-1)/n'?

I don not know how to get frequency vector for my data,that which is not in the normalized frequency range, In fact, it should be in the real frequency range (due to the non-uniform sampling rate).what the matlab code that i should use?

thanks so much .

[NGR MNFD]

Does anyone have an idea on my problem?