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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.
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 sound is based on wave amplitude, so AM reception
can be disrupted by such things as lightning, power lines
and neon signs.
Because FM transmission is based on frequency varia-
tions, interference that consists of amplitude variations
can be filtered out, leaving the reception relatively clear,
which is the major feature of FM radio.
On vehicles so equipped the radio, steering
wheel radio controls and 6 disc CD/DVD changer if
equipped, will remain active for 10 minutes after the
ignition has been turned off, and the driver door has not
been opened. This feature is programmable through the
electronic vehicle information center (EVIC) — if
equipped. Refer to “Delay Power Off to Accessories Until
Exit” under “Personal Settings” in the Electronic Vehicle
Information Center section for details.
CASSETTE TAPE AND PLAYER MAINTENANCE
To keep the cassette tapes and player in good condition,
take the following precautions:
1. Do not use cassette tapes longer than C-90; otherwise,
sound quality and tape durability will be greatly dimin-
2. Keep the cassette tape in its case to protect from
slackness and dust when it is not in use.
3. Keep the cassette tape away from direct sunlight, heat
and magnetic fields such as the radio speakers.
192 UNDERSTANDING YOUR INSTRUMENT PANEL