Name: _____________
EC310 Spring AY2017 Quiz 6
Show your work when performing calculations. On plots, label your axes!
1. On the axes below, sketch the sine wave that matches this equation:
v(t) = 2sin(2π 1000t) volts.
Your sketch should indicate the period. Be sure to label the axes properly.
0
time
2. Sketch the frequency plot of the sine wave from question 1.
3. Sketch the frequency plot of the following signal:
v(t) = sin(2π 200t) + 3sin(2π 300t − π4 ) − 2 cos(2π 500t).
(turn this page over)
Use the following plot of an AM signal in answering the questions that follow.
20
Vmax − Vmin
2
Vmax + Vmin
Vc =
2
V
V − Vmin
m = m = max
Vc Vmax + Vmin
18
Vm =
16
14
12
10
8
6
AM signal
4
2
0
-2
-4
-6
-8
-10
-12
-14
-16
-18
-20
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
time (msec)
4. Find the carrier frequency fc and the message frequency fm.
5. Find Vmax and Vmin and indicate these on the plot.
6. Find Vc (amplitude of the carrier) and Vm (amplitude of the message).
7. Find modulation index, m.
Bonus: Back during the cold war, the Soviet Union was labeled on a map as “U.S.S.R.” What does
USSR stand for?