Okay, so i'm confused about the problem and what's asking me. I'm being told " analyse the signals in time and frequency domain " analysing them in frequency domain means doing the fourier transform and representing the signals right ?

 

In the simplest terms, yes. If you collect a number of samples over some period of time you can then use the fourier transform to tell you what sine waves (with the triple components of frequency, phase, and amplitude) could be added together to reconstruct the signal.

But just bear in mind that it may or may not give you realistic results. A square wave, for example, would give you a large spread of frequencies (a fundamental plus numerous harmonics) even though you may well know that the source that generated the signal contained only simple "on-off" levels. Another problem is that your sampling window will most likely not fall precisely along phase-transition/frequency-shifting boundaries, so the resulting plot will contain triplets not present in the original signal. Noise can distort the plot. A sampling rate below the Nyquist criteria for the source signal will distort the plot. Etc, etc, etc.

That's why we have things like short-time-FFT analysis and wavelet basis functions. But even these don't solve the problem completely. Just a bit of food for thought...

 

What are the signals and what instruments do you have available?

 

Okay, so i'm confused about the problem and what's asking me. I'm being told " analyse the signals in time and frequency domain " analysing them in frequency domain means doing the fourier transform and representing the signals right ?

Hi,

There are a lot of possibilities here actually and this mostly depends on what you were taught in the past because that would narrow down the choice of methods.

There are so many frequency domain representations that you have to know what type to use. Most common is the Fourier Transform and the Fourier Series, but if you are to analyze the circuit itself then there is also a simple sine wave analysis for example which gives you the response of the circuit under sinusoidal excitation.

You must have learned something about this in the past or else i cant see why you would be asked this question unless you suddenly walked into a class on EE Circuits 102 before you took EE Circuits 101, but whatever you can elaborate on here might help people here to understand what you are hoping to accomplish.