what type of signal is this?FIR filters

i am confused as to what type of signal this is when the matlab code is written.

here's ,my code, the variables are linked.

input = xx;

T = 2001;

N = length(t);

freq = abs(fft(input))*2/N;

f = (0:N-1)'/T;

subplot(2,2,1);

plot(input, 'b*-'); % Plot the input as a blue line

xlabel('Time/s');

ylabel('Amplitude');

subplot(2,2,2);

plot(f,freq);

xlabel('Frequency (Hz)')

ylabel('|Y(f)|')

xlim([0 0.5]);

Answer 1

[Sulaymon Eshkabilov]

Here is the corrected code. Time domain vs. Frequency domain analysis of the signal t vs. xx:

load firlab2
%%
input = xx;
dt = t(2)-t(1);          % Sampling time, [s] 
fs = 1/dt;               % Sampling frequency, [Hz]
N = length(t);           % Signal length 
F = abs(fft(input))/N;   % Signal spectrum 
F1 = F(1:N/2+1);
F1(2:end-1) = 2*F1(2:end-1); 
f = fs*(0:(N/2))/N;      % Frequency data  
subplot(211)
plot(t, input, 'b-')     % Input signal in Time domain
xlabel('\it Time, [s]')
ylabel('\it Amplitude')
title 'Signal in time domain'
grid on

subplot(212)
plot(f,F1)           % Input signal spectrum in frequency domain    
title('Single-Sided Amplitude Spectrum of Signal ')
xlabel('\it Frequency, [Hz]')
ylabel('\it Amplitude of Spectrum') 
grid on

[Tianchu Lu]

yeah thanks,would you know what type of signal this is? after its gone through some kinda of filter?