Problem 7.6 A phase angle of 120◦ was added to a 3-MHz signal, causing its
waveform to shift by ∆t along the time axis. In what direction did it shift and by
how much?
Solution: Adding a positive phase angle causes the waveform to shift “backwards”
along the time axis.
At f = 3 MHz,
1
1
1
= µ s.
T= =
f
3 × 106 3
A phase angle addition of 360◦ would shift the waveform by a full period T .
Proportionately, ∆t due to 120◦ is:
120◦
1
1 1
∆t =
T = × µ s = µ s.
360◦
3 3
9
c
All rights reserved. Do not reproduce or distribute. 2013
National Technology and Science Press