User Guide

RM-94

Nokia Customer Care 7 - System Module

32 COMPANY CONFIDENTIAL Issue 1 04/2005

■ Frequency concept

The RF frequency plan is shown below. The VCO operates at the channel frequency multiplied

by two or four depending on the frequency band of operation. This means that the modulated

signals from baseband are directly converted up to the transmission frequency and the re-

ceived RF signals directly down to the baseband frequency.

Figure 13:RF frequency plan

■ RF power supply configuration

All power supplies for the RF unit are generated in the UEM ASIC, which contains among other

functions six pieces of 2.78 V linear regulators (VR2 ... VR7), a 4.8 V switching regulator (VR1)

and two 1.35V voltage references (VrefRF01 and VrefRF02).

The regulators are connected to the RF ASIC, except for VR7, which supplies the VCO. The

4.8V supply is required for the charge pump of the PLL to generate the tuning voltage for the

VCO.

The reference voltages are used as bias reference for the RF ASIC for the RX ADC (analog-

to-digital converter) reference.

All RF supplies can be checked either in Small Signal Chamber or in BB Chamber.

The used power supply configuration is shown in the block diagram below. Values of voltages

are given as nominal outputs of UEM. Currents are typical values.

SM900: 925-960 MHz

SM1800: 1805-1880 MHz

SM1900: 1930-1990 MHz

f/4

Helgo

f/2

PLL

3296-

3980

MHz

I-signal

Q-signal

I-signal

Q-signal

SM1900: 1850-1910 MHz

SM1800: 1710-1785 MHz

SM850: 824-849 MHz

SM900: 880-915 MHz

Buffer

VCTCXO

26 MHz

VCTCXO

AFC