PD17012GF-055_15 Datasheet, PDF (35/84 Pages) Renesas Technology Corp – SINGLE-CHIP MICROCONTROLLER WITH ON-CHIP PRESCALER, PLL FREQUENCY SYNTHESIZER, AND IF COUNTER FOR CAR-MOUNTED FM/MW/LW RADIO

µPD17012GF-055
5. RDS (Radio Data System) FUNCTION
5.1 RDS Data Incorporation
µPD17012GF-055 internally decodes RDSDATA and RDSCLK from the RDS-compound IC. Synchronization
detection is limited to block synchronization, and error correction is not performed.
Block synchronization is detected for the following four types of block patterns.
1 : A–B–C–D
2 : A–B–C'–D
3 : A–B–E–E
4 : A–B–F–F
The method of detecting synchronization is as follows: the synchronous status is checked per block from the
current point to 5 previous blocks before; if synchronization of three or more blocks out of 5 blocks is detected, it is
judged that block synchronization exists.
If block synchronization is not obtained for 1.5 seconds or more, the status of each of TP, TA, and PTY is cleared.
If an error is detected from the incorporated blocks and if block synchronization has taken place, synchronization
detection is performed every 26 bits until the block synchronization is removed.
Figure 5-1. Block Synchronization Detection
OK
OK
NG
OK
NG
NG
OK
OK
OK
OK
A
B
C
D
A
B
C
D
A
B
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
*
*
*
*
*
*
*
*
*
*
*
Blocks are judged
to be synchronized.
Blocks are judged
not to be synchronized.
Blocks are judged
to be synchronized.
(NG0 time) (NG1 time) (NG1 time) (NG2 times)(NG3 times)(NG2 times) (NG2 times)(NG2 times) (NG1 time)
Block synchronization status
Block asynchronization status
∗ : The synchronization status for the preceding 5 blocks is checked. In this case,
if at least 3 blocks are not synchronized out of 5 blocks, the blocks are judged
to be asynchronous.
A to D : Indicates offset check words.
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