LG VX5400 Service Manual page 30

2.3.3 MSM Part
MSM6100 is the core element of CDMA system terminal that includes ARM9TDMI microprocessor core. It
supports both CDMA and Digital FM, operating in both the cellular and PCS spectrums. The subsystems within
the MSM6100 include a CDMA processor, a DFM processor, a multi-standard Vocoder, an integrated CODEC
with earpiece and microphone amplifiers, general-purpose ADC for subsytem monitoring, an ARM9TDMI
microprocessor, and both Universal Serial Bus(USB) and an RS-232 serial interfaces supporting forward and
reverse link data communications of 307.2 Kbps simultaneously. And it also contains complete digital
modulation and demodulation systems for both CDMA and AMPS cellular standards, as specified in
IS-95-A/B/C.
In MSM, coded symbols are interleaved in order to cope with multi-path fading. Each data channel is
scrambled by the long code PN sequence of the user in order to ensure the confidentiality of calls. Moreover,
binary quadrature codes are used based on walsh functions in order to discern each channel. Data created thus
are 4-phase modulated by one pair of Pilot PN code and they are used to create I and Q data.
When received, I and Q data are demodulated into symbols by the demodulator, and then de-interleaved in
reverse to the case of transmission. Then, the errors of data received from viterbi decoder are detected and
corrected. They are voice-decoded at the vocoder in order to output digital voice data.
[Figure 2-2] Block Diagram of Digital/Voice Processing Part
2.3.4 Memory Part
MCP contents 512 Mbits NAND flash memory and 256 Mbits SDRAM. In the Flash Memory part of MCP is
programs used for terminal operation. The programs can be changed through down loading after the assembling
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