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Philips Semiconductors
User Manual of High-End RDS/EON
Car Radio System CCR612 (V0.3)
Application Note
96029
Figure 16 explains how user options can be programmed.
SELECT
> 4 seconds
BAND
FREQ UP
FREQ DOWN
2 SPKRS / 4 SPKRS
LOUD ON / LOUD OFF
TA LVL
SELECT
6 sec
timeout
EXIT
Figure 16 Programming user options
6.5 RDS / RBDS functions
The RDS / RBDS functions are available only if the radio is tuned to an FM band.
6.5.1 AF follow mode
The AF follow mode mechanism is switched on/off by pressing the AF key short. When AF follow mode
is on, the AF icon is switched on. If no RDS data is received, the AF icon blinks.
In AF follow mode, the radio measures at regular intervals, (interval time depends on the signal quality),
the signal level atfrequencies that are mentioned in the list ofalternative frequencies (AF’s) for the current
station. For these measurements, the reception of the current station is interrupted for a very short period
(appr. 7 milliseconds), and it is hardly noticeable. If an alternative frequency is stronger than the current
stationfor afew seconds(dependingon thesignal quality),theradio switchesto thatalternativefrequency.
It switches also if the quality of the current station becomes suddenly very poor, or if its RDS data cannot
be received. The quality of a station is a function of signal level as well as multipath condition.
The AF follow mechanism is always active when AF follow mode is on, even when the radio is muted or
is in CD-changer or cassette or external mode.
When the user starts a tuning action (band, preset, FREQ-UP / FREQ-DOWN), or when the radio is
switched off, the new frequency and the AF list are stored in NVM. These will be used later on when
selecting the preset again.
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