data=load ('050105B.dat');
time = data (:,1);
inlet050105B = data (:,2);
outlet050105B = data (:,3);
thrust050105B = data (:,4);
X1 = fft(outlet050105B);
N1 = length(X1);
X1(1) = [];
power1 = abs(X1(1:N1/2)).^2;
freq1 = 500*((1:N1/2)/(N1/2));
subplot(2,1,1)
plot(time,inlet050105B,'g-',time,outlet050105B,'b-',time,thrust050105B,'r-'),title('050105B static fire')
subplot(2,1,2)
plot(freq1,power1,'b-'),title('050105 chamber pressures FFT')