4. Level 3 Repair
4.1 The Block Diagram of Logic part
4.2 RF Block Diagram
Note:
ST009 support GSM850/900/DCS1800/PCS1900 four frequency channels in
the front module, This product’s front module gathers PA and Antenna Switch into one
chip, which makes it different from the other mobile phone, also the Tranceiver part and
base belt part gather into one chip.
As showed on the diagram, the wireless signal is transferred to receiving end from
antenna end, then enter PA module, pass Antenna Switch to select frequency chennal
first, then pass SAW Filter, hight-frequency signal enter into E-GOLDradio chip directly,
passing LNA low-voice amplifier to amplify the received signal, then to mix frequency
channel with the base vibrating frequency channel in base vibrating module(
TRANCE
is
Zero intermediate frequency), wave and moldulation cause I,Q differential signal, then to
be balanced, speech sounds and channel decode, and finally pass through DAC digital
mold transferring output analogy voice signal.
On the sending end, voice signal input by MIC shifts into digital signal through ADC, to
make the voice and channel code, GMSK modulation and frequency compounding, at
last amplified by PA and then output by Antenna.
