Analog Baseband - LG F1200 Service Manual

3.6 Analog Baseband

(1) General Description
Syren is Analog Baseband (ABB) Chip supports GSM900, DCS1800, PCS1900, GPRS Class
10 with Digital Baseband Chip. Syren processes GSM modulation/demodulation and power
management operations.
Block Description
- Audio Signal Processing & Interface
- Baseband in-phase (I), quadrature (Q) Signal Processing
- Auxiliary RF converters
- Five-channel analog-to-digital converters (ADC)
- Six Low-dropout (LDO), linear voltage regulators targeted core, general I/O, memory I/O,
SIM I/O
- LDO voltage regulators dedicated to the USB interface
- High voltage (20V) Li-Ion or Ni-MH battery charging control
- Voltage detectors (with power-off delay)
- Voice Codec
(2) Audio Signal Processing & Interface
Audio signal processing is divided Uplink path and downlink path. The uplink path amplifies the
audio signal from MIC and converts this analog signal to digital signal and then transmit it to
DBB Chip. This transmitted signal is reformed to fit in GSM Frame format and delivered to RF
Chip. MICBIAS is 2.0V level.
The downlink path amplifies the signal from DBB chip and outputs it to Receiver (or Speaker).
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3. TECHNICAL BRIEF