Analog Main Processor - LG 512W Service Manual

3.7 Analog Main Processor

A. Baseband Transmit section
This section generates in-phase and quadrature BB modulated GMSK signals (BT = 0.3) in
accordance with GSM 05.05 Phase 2 specifications.
The transmit channel consists of a digital GMSK modulator, a matched pair of 10-bit DACs and a
matched pair of reconstruction filter.
B. Baseband Receive section
This section consists of two identical ADC channels that process baseband in-phase(I) and
quadrature(Q) input signals.
Each channel consists of a coarse switched capacitor input filter, followed by a high-order sigma-
delta modulator and a lowpass digital filter.
C. Auxiliary section
This section contains two auxiliary DACs(AFC DAC, IDAC) for system control.
This section also contains AUX ADC and Voltage Reference.
AUX ADC: 6 channel 10 bits
AFC DAC: 13 bits
IDAC: 10 bits
D. Voiceband section
Receive audio signal from MIC. LG-512W use differential configuration.
Send audio signal to Speaker. LG-512W use differential configuration.
It interconnect with external device like main microphone, main speaker, ear-phone and Hands free
kit through the VINNORP, VINNORN, VOUTNORP, VOUTNORN, VINAUXP, VINAUXN,
VOUTAUXP, VOUTAUXN and BUZZER port.
VINNORP, VINNORN: Main MIC positive/negative terminal
VOUTNORP, VOUTNORN: Main Speaker positive/negative terminal
VINAUXP, VINAUXN: Hands free kit mike positive/negative terminal
VOUTAUXP, VOUTAUXON: Hands free kit speaker positive/negative terminal
BUZZER: Buzzer Output terminal
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3. TECHNICAL BRIEF