User Guide

The power control loop is enabled and disabled by writing an appropriate register in N7501 RF ASIC. In case

of dual slot transmission, the output power is ramped down between the consecutive slots.

GSM PA module

A single GSM/EDGE PA module contains two separate amplifier chains, one for EGSM900 and another for

GSM1800/1900. Both amplifiers have a battery supply connection and two bias current inputs.

Frequency synthesizers

RF has separate synthesizers for Rx and Tx. Both synthesizers consist of:

• PLL (Phase-Locked Loop)

• loop filter

• VCO (Voltage Controlled Oscillator)

• balun

The VCO frequencies are locked by PLLs into a reference oscillator, VCTCXO (Voltage Controlled Temperature

Compensated Crystal Oscillator).

The PLLs are located in RF ASICs and controlled via RFBus.

Reference oscillators

A 38.4MHz VCTCXO is used as a reference oscillator for the frequency synthesizers.

Regulators

RF ASICs contain integrated regulators to supply regulated voltages for their internal circuitry and other RF

parts.

RM-86

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