## Frequency response of a system operating at a fixed frequency

I am trying to simulate the behavior of a system in simulink. I am providing a sinusoidal input with a fixed frequency (e.g. 0.3 Hz) and I am exporting the results in matlab. I want to verify that at this operating frequency, the frequency response is flat. Once done that I’ll increase the frequency and so on untill I reach a decrease in the frequency response of -3dB.

However I am facing dissiculties in evaluating this.

I tried doing something like this:

Y_measured = fft(measured);

Y_target = fft(target);

Y = Y_measured./Y_target;

amplitude = abs(Y);

phase = unwrap(angle(Y(1:N/2+1)));

I then plotted the amplitude and the phase over time.

The fact is that being the system evaluated at a fixed frequency, the frequency response diagram loses a lot of significance and I become only intrested in what would be a specific point of the diagram (I guess?).

So in conclusion:

Is this a correct way of evaluating the frequency response of my system?

What would be an efficien way of plotting and showing the results?

Thank you.I am trying to simulate the behavior of a system in simulink. I am providing a sinusoidal input with a fixed frequency (e.g. 0.3 Hz) and I am exporting the results in matlab. I want to verify that at this operating frequency, the frequency response is flat. Once done that I’ll increase the frequency and so on untill I reach a decrease in the frequency response of -3dB.

However I am facing dissiculties in evaluating this.

I tried doing something like this:

Y_measured = fft(measured);

Y_target = fft(target);

Y = Y_measured./Y_target;

amplitude = abs(Y);

phase = unwrap(angle(Y(1:N/2+1)));

I then plotted the amplitude and the phase over time.

The fact is that being the system evaluated at a fixed frequency, the frequency response diagram loses a lot of significance and I become only intrested in what would be a specific point of the diagram (I guess?).

So in conclusion:

Is this a correct way of evaluating the frequency response of my system?

What would be an efficien way of plotting and showing the results?

Thank you. I am trying to simulate the behavior of a system in simulink. I am providing a sinusoidal input with a fixed frequency (e.g. 0.3 Hz) and I am exporting the results in matlab. I want to verify that at this operating frequency, the frequency response is flat. Once done that I’ll increase the frequency and so on untill I reach a decrease in the frequency response of -3dB.

However I am facing dissiculties in evaluating this.

I tried doing something like this:

Y_measured = fft(measured);

Y_target = fft(target);

Y = Y_measured./Y_target;

amplitude = abs(Y);

phase = unwrap(angle(Y(1:N/2+1)));

I then plotted the amplitude and the phase over time.

The fact is that being the system evaluated at a fixed frequency, the frequency response diagram loses a lot of significance and I become only intrested in what would be a specific point of the diagram (I guess?).

So in conclusion:

Is this a correct way of evaluating the frequency response of my system?

What would be an efficien way of plotting and showing the results?

Thank you. frequency, amplitude MATLAB Answers — New Questions