Mazda CX-7 2007 Workshop Manual page 1456

REFERENCE[RADIO]
1. Multipath Noise
• Signals from an FM transmitter are a high
frequency and similar to beams of light because
they do not bend around corners, but they do
reflect. Since FM signals can be reflected by
obstructions, it is possible to receive both the
direct signal and the reflected signal at the same
time. This causes a slight delay in reception and
may be heard as a broken sound or a distortion.
2. Flutter/Skip Noise
• Signals become weak in valleys between
mountains, tall building, and other obstacles.
When the vehicle passes through such an area,
the reception conditions may change suddenly,
resulting in annoying noise.
3. Stereo and Monaural Receptions
• As signals become weak, noise may appear more in stereo reception. Comparing to stereo reception, noise in
monaural receptions is relatively less striking.
Measures in Audio System
Separation control
• Utilizing the characteristic of monaural reception that noise is relatively less striking than stereo reception, the
audio system automatically changes the reception from stereo to monaural and lessens annoying noise when
signals become weak or a multipath phenomenon occurs.
High tone control
• When signals become weak or a multipath phenomenon occurs, the audio system restrains volume level in
high frequency band and lessens annoying noise.
Effect Setting of Separation Control and High Tone Control
• The separation and high tone controls influence sound quality, Therefore they are specifically tuned for
individual model. (Comparison of characteristic must be done on the same models)
High tone setting
Noise restraint setting
09-03E–10
SYMPTOM TROUBLESHOOTING [RADIO]
Less effective range
Wider effective range
Noise is conspicuous
Noise is less conspicuous
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