# energy spectral density

#### andrew132

Joined Feb 2, 2017
96
hey i need help in how to calculate energy spectral density of
Rx=e^(j2*pi *f(t))

#### RBR1317

Joined Nov 13, 2010
490
Is the function f(t) defined anywhere in the problem?

What if f(t) were a constant? Could you calculate the energy spectral density then?

What if f(t) varied with time? Could Rx be described as a frequency-modulated carrier wave?

#### andrew132

Joined Feb 2, 2017
96
Is the function f(t) defined anywhere in the problem?

What if f(t) were a constant? Could you calculate the energy spectral density then?

What if f(t) varied with time? Could Rx be described as a frequency-modulated carrier wave?
i dont know a thing about energy spectral density

#### RBR1317

Joined Nov 13, 2010
490
Since there is no information about the function f(t), have you considered the possibility that the objective of the task is not to calculate anything regarding spectral density but rather to recognize what type of signal Rx is and what relationship it has to f(t)?

#### shteii01

Joined Feb 19, 2010
4,667
2pif is omega.

All you have to do is find the absolute value of e^jw(t), then square the absolute value, that is the energy spectral density.

#### RBR1317

Joined Nov 13, 2010
490
...find the absolute value of e^jw(t), then square the absolute value...
I have difficulty relating this to Parseval's Theorem for energy spectral density of an aperiodic signal. Given a time domain signal Rx(t) and its Fourier transform Rx(ω), [if the signal is periodic we are dealing with Fourier series], then the energy spectral density is given by the square of the absolute value of the Fourier transform of the time domain signal.