# Finding frequency components

1. Apr 2, 2017

### tai man

1. The problem statement, all variables and given/known data
Which frequency components are present in the amplitude-modulated (AM) signal A(t)=[1+asin(2πfmt)]A0sin(2πfct), where fm= 3.5 kHz, fc = 540 kHz, and a = 0.1?

2. Relevant equations
A(t)=[1+M(t)]A0sin(2πfct),
where modulating signal M(t) = sin(2πfm t + ∅),
high frequency carrier = A0sin(2πfct),
fc : Carrier frequency
fm : Modulation frequency
3. The attempt at a solution
I wrote down 'Carrier frequency and modulation frequency are presented' at first, but now I am not sure that the question requires a numerical answer or not.

Last edited: Apr 2, 2017
2. Apr 2, 2017

### Staff: Mentor

It likely requires numerical answers as there is sufficient information given to perform the necessary calculations.

Look up "amplitude modulation" and review the theory. Pay attention to the discussion of sidebands. The concept of beat frequencies applies.

3. Apr 2, 2017

### tai man

So are we finding the numerical answers of the carrier frequency and the modulating signal frequency?

4. Apr 2, 2017

### Staff: Mentor

You're given those values in the problem statement. You are to find the resulting frequencies that appear in the transmitted signal.

5. Apr 2, 2017

### tai man

OK Thank you so much