Figure 5. Baseband Block Diagram - Motorola c18 Developer's Manual

Cellular engine module description

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Table Of Contents

Table of Contents

3.1.2.3

Frequency Generation

There are three RF frequencies generated to enable frequency conversions within the radio:

• Front-end-down and Front-end-up Conversion LO Frequency: The frequency plan is designed so that the Rx front-end-down

conversion LO and the Tx front-end-up conversion LO are the same frequency, which is generated in the dual synthesizer

IC. This LO is fed into the RFR3300 IC, where it drives the down-convert mixers and from where it is also redirected to the

RFT3100 IC, where it drives the single sideband up-convert front-end mixers. The basic synthesizer frequency is around

2 GHz, which supports the 1.9GHz band. The internal divide-by-two circuitry within the RFR3300 is able to produce

one-half the LO frequency to support the 800MHz band as well.

• The frequency required for the quadrature down-convert LO (translating the signal from IF to baseband) is generated from

the dual-synthesizer IC, as well as from an on-chip VCO in the IFR3300 IC.

• The quadrature up-convert LO (translating the signal from baseband to IF) is generated from an on-chip synthesizer on the

RFT3300 IC, as well as from an external VCO and loop filter circuitry.

All frequency generation uses a common 19.2MHz x-stall reference oscillator.

3.1.2.4

Baseband

This section describes power management, digital processing, memory and external interface requirements.

Figure 5 shows the baseband block diagram:

INTERFACE

CONNECTOR

GENERAL PURPOSE ADC INPUTS

LCD INTERFACE

98-08901C63-A

RUIM

UART2/RUIM INTERFACE

UART1 INTERFACE

USB

TRANSCIEVER

KEYPAD INTERFACE

PCM AND GPIO INTERFACE

AUDIO INTERFACE

VREG_MSMA

VREG_MSMC

HARNESS

IGNITION

ON/OFF

VCC

PM1000