Wideband Codec; Vocoder Subsystem - LG KS20 Operating Instructions Manual

3. TECHNICAL BRIEF
3.8.5. Serial Bus Interface(SBI)
The MSM7200 device's SBI is designed specifically to be a quick, low pin count control protocol for
QUALCOMM's RTR6275 and PM7540 ASICs. Using the SBI, the RTR6275 and PM7540 devices
can be configured for different operating modes and for minimum power consumption, extending
battery life in Standby mode. The SBI also controls DC baseband offset errors.

3.8.6. Wideband CODEC

The MSM7200 device integrates a wideband voice/audio CODEC into the mobile station modem
(MSM). The CODEC supports two differential microphone inputs, one differential earphone output, one
single-ended earphone output, and a differential analog auxiliary interface.
The CODEC integrates the microphone and earphone amplifiers into the MSM6280 device, reducing
the external component count to just a few passive components.
The microphone (Tx) audio path consists of a two-stage amplifier with the gain of the second stage set
externally. The Rx/Tx paths are designed to meet the ITU-G.712 requirements for digital transmission
systems.

3.8.7. Vocoder Subsystem

The MSM7200 device's QDSP4000 supports AMR,FR,EFR and HR. In addition, the QDSP4000 has
modules to support the following audio functions: DTMF tone generation, DTMF tone detection, Tx/Rx
volume controls, Tx/Rx automatic gain control (AGC), Rx Automatic Volume Control (AVC), EarSeal
Echo Canceller (ESEC), Acoustic Echo Canceller (AEC), Noise Suppression (NS), and programmable,
13-tap, Type-I, FIR, Tx/Rx compensation filters. The MSM7200 device's integrated ARM9TDMI
processor downloads the firmware into the QDSP4000 and configures QDSP4000 to support the
desired functionality.
3.8.8. ARM Microprocessor subsystem
The MSM7200 device uses an embedded ARM1136-J, ARM926EJ-S microprocessor. This
microprocessor, through the system software, controls most of the functionality for the MSM device,
including control of the external peripherals such as the keypad, LCD, RAM, ROM, and EEPROM
devices. Through a generic serial bus interface (SBI) the ARM926EJ-S configures and controls the
functionality of the RTR6275 and PM7540 devices.
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