PD178016GC-051_15 Datasheet, PDF (44/96 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCONTROLLER WITH BUILT-IN PRESCALER, PLL FREQUENCY SYNTHESIZER, AND IF COUNTER FOR AUTOMOTIVE FM/MW/LW RADIO APPLICATIONS

µPD178016GC-051
(ii) When changing the tunable frequency
AF operation is disabled after the frequency has been changed until the reception state is stabilized.
Disable time
3 seconds
(iii) When power is first applied
AF operation is disabled until reception stabilizes.
Disable time
5 seconds
(iv) If AF operation fails repeatedly in a tunnel
If the S • M reading range changes from A to C, and if the AF operation has failed in range C, the system
judges that the vehicle is currerntly in a tunnel.
If this judgment is made, AF operation is disabled depending on the number of times the operation has
failed, so that AF operation is not retried frequently.
Disable time
(Number of successive failures - 1) × 60 seconds
(9 minutes MAX.)
The number of successive failures is cleared in the following cases:
• When the tunable frequency is changed (except during AF operation/B.S./EON operation)
• If S • M reading range is not in range C
• If AF operation/B.S./EON operation is successful
(v) If AF operation is repeatedly successful in the same region
<1> If the AF operation (where S • M reading range is A) is successful in the decode state, the frequency
at which the operation succeeded is recorded.
<2> If the number of stations for which the AF operation succeeded is three or less within one hour when
<1> is repeatedly successful, it is judged that all the stations are suffering from reception abnormalities
such as multipath.
However, this judgment is not made until <1> succeeds six times in a row.
<3> If a fault such as multipath occurs, the AF operation is immediately started even if the AF operation has
been successful; therefore, the AF operation is disabled.
Disable time
10 seconds
<4> The frequency recorded in <1> is cleared in the following cases:
• When the tunable frequency is changed (except during AF operation/B.S./EON operation)
• When the AF operation succeeds in the S • M reading range (where the S • M reading range is B or
C)
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