1B-18
Chapter 1B
AUDIO
AUDIO SYSTEM cont.
GENERAL INFORMATION
Audio system faults
In case of faulty operation, consult your Holden Dealer.
Antenna
The AM antenna is incorporated in the right hand rear quarter window and the FM
antenna is incorporated in the tailgate window. The FM antenna is part of the heated
rear window demister pattern. This type of antenna may be adversely affected by dirt
on the inside of the window or damage to the antenna pattern.
Radio reception
Due to varying reception locations, audio systems have performance limitations that
may on occasions create the impression that your radio is malfunctioning.
AM and FM
There are two types of radio broadcasts in Australia. Amplitude Modulation (AM)
in which the amplitude of the signal is varied to produce the sound and Frequency
Modulation (FM) in which the frequency is varied to produce the sound.
Range
AM broadcasts tend to follow the earth’s curvature and also reect from the upper
atmosphere which enables long range reception especially after sunset.
FM transmissions are basically line-of-sight (similar to TV signals) and are reected by
buildings, mountains etc. but not by the upper atmosphere.
Interference
Interference is caused by local electrical disturbances. This can affect the amplitude of
the signal being received.
AM signals are more prone to this type of interference than FM signals. This type of
interference has little or no effect on the frequency of the received signal thus AM is
susceptible to interference from power lines, uorescent lighting, neon signs, trafc
light control circuits, overhead tram wires and electrical storms.
With FM reception these amplitude variations are ltered out leaving a relatively clear
signal, (refer to Peculiarities of FM mobile reception on the next page) making this one
of the major advantages of FM broadcasts.
CAPTIVA BOOK.indb 18 30/05/2007 12:49:08 PM
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