function [ ] = plotFrequency( signal, fs ) %Define number of samples to take f = 400; %Hz %Define signal t = 0:1/fs:1-1/fs; signal = sin(2*pi*f*t); %Plot to illustrate that it is a sine wave plot(t, signal); title('Time-Domain signal'); %Take fourier transform fftSignal = fft(signal); %apply fftshift to put it in the form we are used to (see documentation) fftSignal = fftshift(fftSignal); %Next, calculate the frequency axis, which is defined by the sampling rate f = fs/2*linspace(-1,1,fs); %Since the signal is complex, we need to plot the magnitude to get it to %look right, so we use abs (absolute value) figure; plot(f, abs(fftSignal)); title('magnitude FFT of sine'); xlabel('Frequency (Hz)'); ylabel('magnitude'); end