function [Ax,Ay,ratio] = fft_two_signals(x,y,z) 
% Performs FFT Analysis of the acceleration signals
% and returns their amplitudes Ax, Ay, and ratio.
% Inputs are signals x and y, and driving frequency z.
%% User Inputs
% Sample rate of the Arduino, 1000 corresponds to 115200 Baud
Fs = 1000;
%% Processing Code
% No code here needs to be changed by the user.
x=x-mean(x);
y=y-mean(y);
T = 1/Fs;
L=length(x);
X = fft(x);
Y = fft(y);
f = Fs*(0:(L/2))/L;
P2X = abs(X/L);
P1X = P2X(1:floor(L/2)+1);
P1X(2:end-1) = 2*P1X(2:end-1);
P2Y = abs(Y/L);
P1Y = P2Y(1:floor(L/2)+1);
P1Y(2:end-1) = 2*P1Y(2:end-1);
% Refine the range to driving frequency so that the
% max function gives the amplitude at the frequency
% we are interested in:
P1Y=P1Y(round(z/f(2))-25:round(z/f(2))+25);
P1X=P1X(round(z/f(2))-25:round(z/f(2))+25);
[Ay,I2]= max(P1Y);
f2=f(I2);
[Ax,I1]= max(P1X);
f1=f(I1);
ratio = Ay/Ax;
% Code used for plotting, visualization
figure
plot(f(round(z/f(2))-25:round(z/f(2))+25),P1X)
xlim([z-5,z+5])
hold on
plot(f(round(z/f(2))-25:round(z/f(2))+25),P1Y)
% Print out answers
fprintf('The amplitude of the base is: %5.4f\n',Ax)
fprintf('The amplitude of the mass is: %5.4f\n',Ay)
fprintf('The magnification ratio is: %5.4f\n',ratio)
end