Radio General Information; Radio Broadcast Signals; Two Types Of Signals - Dodge Caravan 2008 Owner's Manual

236 UNDERSTANDING YOUR INSTRUMENT PANEL
To Manually Calibrate the Compass
Start the engine, and leave the transmission in the P
(Park) position. Press and hold (approximately 10 sec-
onds) the odometer/trip odometer reset button until the
current variance zone number is displayed. Release the
odometer/trip odometer reset button, then press and
hold again (approximately 10 seconds), until the direc-
tion is displayed with the "CAL" indicator on continu-
ously in the display. To complete the compass calibration,
drive the vehicle in one or more complete 360 degree
circles under 5 mph (8 km/h) in an area free from power
lines, large metallic objects, until the "CAL" indicator
turns off. The compass will now function normally.

RADIO GENERAL INFORMATION

Radio Broadcast Signals

Your new radio will provide excellent reception under
most operating conditions. Like any system, however, car
radios have performance limitations, due to mobile op-
eration and natural phenomena, which might lead you to
believe your sound system is malfunctioning. To help
you understand and save you concern about these "ap-
parent" malfunctions, you must understand a point or
two about the transmission and reception of radio sig-
nals.

Two Types of Signals

There are two basic types of radio signals... AM or
Amplitude Modulation, in which the transmitted sound
causes the amplitude, or height, of the radio waves to
vary... and FM or Frequency Modulation, in which the
frequency of the wave is varied to carry the sound.