Radio general information, Radio broadcast signals, Two types of signals – Jeep 2007 Wrangler User Manual

Page 216: Electrical disturbances, Am reception

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Outside Temperature
If the outside temperature is more than 131°F (55°C), the
display will show 131°F (55°C). When the outside tem-
perature is less than

Ϫ40°F (Ϫ40°C), the display will

show

Ϫ40°F (Ϫ40°C).

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.

Electrical Disturbances

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.

216

UNDERSTANDING YOUR INSTRUMENT PANEL

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