tda7333 STMicroelectronics, tda7333 Datasheet - Page 10

• Manufacturer Part Number: tda7333
• Description: Rds/rbds Processor
• Manufacturer: STMicroelectronics

TDA7333
7.6 Group and block synchronization module
The group and block synchronization module has the following features :
Figure 9. Group and block synchronization block diagram
This module is used to acquire group and block synchronization of the received RDS data stream, which is pro-
vided in a modified shortened cyclic code. For the theory and implementation of the modified shortened cyclic
code, please refer to the specification of the radio data system (RDS) EN50067.
It further detects errors in the data stream. Depending on the quality bit information of the demodulator an error
correction is made.
The RDS data bytes are available to the software together with status bits giving an indication on the reliability
of the data.
It also extracts TA information which can be used as interrupt source (cf page 12).
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– Hardware group and block synchronization
– Hardware error detection
– Hardware error correction using the quality bit information of the demodulator
– Hardware synchronization flywheel
– TAinformation extraction
– reset by software (ar_res)
BLOCK D
BLOCK A
BLOCK B
AR_RES
TAEON
RDSCLK
RDSDAT
RDSQAL
TA
Demodulator
from RDS
read only
Correction
logic
rds_bd_h,rds_bd_l
RDSDAT(15:0)
Syndrome register
Quality bit counter
RDS block counter
S(9:0)
Correct. pat.
Group & Block Synchronization Control Block
S(4:0)
Corrected
Data_OK
Syndrom zero
ABH
DBH
BLOCKE detected
read only
CP(9:5)
rds_corrp
Block
missed
read only
Q(3:0)
QU(0:3)
rds_qu
bit_int
read/write
set
next
RDS
bit
rds_int
res
new
Block
available
set
int