Radio General Information; Radio Broadcast Signals; Two Types Of Signals; Electrical Disturbance - Dodge 2009 Journey Owner's Manual

CALIBRATE COMPASS
Refer to "Manual Compass Calibration" under "Com-
pass Display."

RADIO GENERAL INFORMATION

Radio Broadcast Signals

The 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.
UNDERSTANDING YOUR INSTRUMENT PANEL 233

Two Types of Signals

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

Electrical Disturbance

Radio waves may pick up electrical disturbances during
transmission. They mainly affect the wave amplitude,
and thus remain a part of the AM reception. They
interfere very little with the frequency variations that
carry the FM signal.

AM Reception

AM sound is based on wave amplitude, so AM reception
can be disrupted by such things as lightning, power lines
and neon signs.
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