Only For Training And Service Purposes - LG KG290 Service Manual

• Baseband Transmit section
This Section is designed to support GMSK and 8-PSK for both single-slot and multislot applications.
And it is generated in-phase and quadrature BB modulated GMSK & 8-PSK signals. The transmit
channel consists of a digital GMSK & 8-PSK modulator, a matched pair of 10-bit DACs and a
matched pair of reconstruction filter. The GMSK modulator which is used for GSM applications. And
the 8-PSK modulator which is used for EDGE applications.
• Baseband Receive section
This section is designed to support GMSK and 8-PSK applications. And is consists of two identical
ADC channels that process baseband in-phase and quardrature input signals. Each channel consists
of a coarse switched capacitor input filter, followed by a highorder sigma-delta modulator and a low-
pass digital filter.
• Auxiliary section
The AD6852 Auxiliary Section includes a Phase Locked Loop, Automatic Frequency Control (AFC)
DAC, voltage reference buffers, an Auxiliary ADC, and light controllers.
♦ Low-Noise Voltage Reference and Voltage Reference Buffers
The AD6852 provides a low-noise voltage reference and several voltage buffers which produce
isolated references. The REF voltage is directly used as a reference for analog voltage regulators.
The REF voltage is used along with internal reference buffers to provide references for all of the
AD6852 digital-to-analog and analog to-digital converters. The REFBB voltage is used as a
reference for the baseband transmit and baseband receive section ADCs and DACs. The
REFOUT voltage is provided for use with external devices. For example, the REFOUT voltage may
be applied to measure crystal temperature using a thermistor. The REFCHG voltage is also
provided for use with external devices. For example, the REFCHG voltage may be applied to
measure battery temperature using a thermistor. The AD6852 provides automatic activation of the
REFBB buffer. When the baseband transmit path or baseband receive path are active, the REFBB
buffer is active.
♦ Automatic Frequency Control (AFC) DAC
The AD6852 AFC DAC is a 13-bit Sigma-Delta DAC that intrinsically does not exhibit differential
nonlinearity. Input data stream is sent into converted via Control Serial Port. AFCDACM (0x16) and
AFCDACL (0x17 ) registers allow to fetch in bits 15-6 and 9-0 respectively. In typical applications,
the AFC DAC must often remain active while all other converters are idle. To minimize system
supply current in this condition, the AFC DAC may operate with the master clock idle. The AFC
DAC uses a low-power internal oscillator to maintain a stable output voltage based on the last
digital input value.
Copyright © 2007 LG Electronics. Inc. All right reserved.

Only for training and service purposes

3. TECHNICAL BRIEF
- 43 -
LGE Internal Use Only