Frequency Spectrum plot of original and reconstructed signal

I have an original signal and a reconstructed signal using first order hold and i want to plot both their frequency spectrum plots. Can you guide me how to do so

t=0:0.01:1;

x=sin(2*pi*f*t);

t2=linspace(0,1,1/0.01);

n=0:1/fs:1;

x1=interp1(n,xs,t2,'linear'); %xs is discrete signal

[Paul]

The following variables are not defined: f, fs, and xs. Even if they were, it's unclear what the objective is. x is a signal sampled at 100 Hz. Is x1 supposed to be x interpolated to higher sampling frequency?

Also, linear interpolate isn't really a first-order-hold (FOH). The FOH exrtrapolates from the previous two points in the signal. Linear interpolation interpolates between the current point and the next point.