LG GB110, Service Manual

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16
mobile phone with
all its peripherals on a 4-layer PCB.
3.1.3 System Platform Application
X-GOLDTM102 was developed for very low cost Dual Band GSM/GPRS system solutions.
Here are some potential System Platform configurations that can be built with X-GOLDTM102
Solution:
3.1.4 GSM System Description
The X-GOLDTM102 is suited for mobile stations operating in the GSM850/900/1800/1900 bands.
In the receiver path the antenna input signal is converted to the baseband, filtered, and then
amplified to target
level by the RF transceiver chip set. Two A-to-D converters generate two 6.5 Mbit/s data streams.
The decimation
and narrowband channel filtering is done by a digital baseband filter in each path. The DSP
performs:
1. The GMSK equalization of the received baseband signal (SAIC support available)
2. Viterbi channel decoding supported by an hardware accelerator.
The recovered digital speech data is fed into the speech decoder. The X-GOLDTM102 supports
fullrate, halfrate,
enhanced fullrate and adaptive multirate speech CODEC algorithms.
The generated voice signal passes through a digital voiceband filter. The resulting 4 Mbit/s data
stream is D-to-A
converted by a multi-bit-oversampling converter, postfiltered, and then amplified by a
programmable gain stage.
The output buffer can drive a handset ear-piece or an external audio amplifier, an additional output
driver for
external loud speaker is implemented.
In the transmit direction the differential microphone signal is fed into a programmable gain amplifier.
The prefiltered
and A-to-D converted voice signal forms a 2 Mbit/s data stream. The oversampled voice signal
passes a digital
decimation filter.