tda7333 STMicroelectronics, tda7333 Datasheet - Page 8

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

TDA7333
Figure 7. Phase Response of the RDS Bandpass Filter
The output sample of the bandpass filter is picked up from a linear interpolator with sinc2 characteristics. The
interpolation factor is 32. A zero cross detection is simply formed by taking the sign bit of the interpolated signal.
This signal which contains only phase informations is processed by the RDS Demodulator.
7.5 Demodulator
– The demodulator includes :
– RDS quality indicator with selectable sensitivity
– Selectable time constant of 57kHz PLL
– Selectable time constant of bit PLL
– time constant selection done automatically or by software
Figure 8. Demodulator Block Diagram
8/21
from RDS group and block synchronisation
to RDS group and block synchronisation
(8,550 or 8,664 MHz)
1
2
3
3
2
1
0
module:
RD
RDSDAT
RDSQUAL
AR_RES
mclk
MPX
5.6
module:
5.65
(digital Filter)
Input-stage
Half Wave
Integrator
Cosine comp.
Sine comp.
Phase of RDS Filter
Frequency [Hz]
ARI-indicator
5.7
mclk
1187.5Hz
PLL
Half Wave
Extractor
57 kHz PLL
Clock Generator
5.75
RDS Data
Extractor
RDS Quality
Extractor
frequency
offset comp.
5.8
x 10
4