TDA7705_10 Datasheet, PDF (11/42 Pages) STMicroelectronics – Highly integrated tuner for AM/FM car radio

TDA7705
Function description
2.6
IF A/D converters
A high performance IQ-IFADC converts the IF-signal to digital IF for subsequent digital
signal processing.
2.7
Audio D/A converters
A stereo DAC provides the left / right audio signals after IF-processing and stereodecoding
by the DSP.
2.8
VCO
The VCO is fully integrated without any external tuning component. It covers all FM
frequency bands including EU, US , Japan, EastEU, Weatherband and AM-bands including
LW, MW, SW.
2.9
PLL
The high speed tuning PLL is able to settle within about 300 µs for fast RDS applications.
The frequency step can be as low as 5 kHz in FM and 500 Hz in AM.
2.10
Crystal oscillator
The device works with a 37.05 MHz fundamental tone crystal, and can be used also with a
3^rd overtone 37.05 MHz crystal.
2.11
DSP
The DSP and its hardware accelerators perform all the digital signal processing. The main
program is fixed in ROM. Control parameters are copied in RAM and are accessible and
modifiable there, thus allowing parametric performance optimization.
It performs:
● digital down-conversion of IF
● bandwidth selection with variable controlled bandwidth
● FM and AM noiseblanking
● FM/AM demodulation with softmute, high-cut, weak signal processing and quality
detection
● FM stereo decoding with stereo blend
● RDS demodulation including error correction and block synchronization with generation
of an RDS interrupt for the main µP
● Autonomous control of RDS-AF tests
● Self alignment of preselection tuning
Doc ID 15938 Rev 8
11/42