Nokia RM-132 Service Manual & Parts Manual

Also see for N73 - Smartphone 42 MB: Specification sheet User guide Get started Get started User guide

Contents

Nokia RM-132 Service Manual & Parts Manual Manual pdf 336 page image

PA DCDC converterThe DCDC converter is controlled by 5 bit DA (DAC101) converter in RF ASIC N7500. The converter is controlledvia RFBus. The DCDC converter limits the lowest supply voltage to 1.3 V. At the highest power levels, the DCDCconverter output settles nominally to 3.1 V.GSM transmitterAn analogue IQ modulated signal is fed to the RF ASIC from Digital BB. It is first low pass filtered then routedto the GSM modulator. The appropriate routing after the modulator is selected by biasing either GSM850/EGSM900 or GSM1800/1900 variable gain amplifier.After the VGA stage, the signal exits the RF ASIC. In case of GSM1800/1900, the signal goes directly to the GSMPA module. In case of GSM850/EGSM900, the PA module is preceded by a switchable SAW filter. After the filter,the signal is fed to GSM TX front-end module (TXFEM), which also contains the switch matrix. It routes theoutput GSM signal to the single feed antenna switch and then to the antenna.GSM PA moduleThe TXFEM module contains two separate amplifier chains, one for GSM850/EGSM900 and another forGSM1800/1900. Both amplifiers have a battery supply connection and two bias current inputs.Frequency synthesizersThere are two separate synthesizers for WCDMA Rx and WCDMA Tx / GSM Tx / Rx. This allows the duplexseparation to be set according the network settings in the WCDMA mode.The VCOs are locked by PLLs into a reference oscillator, VCTCXO (Voltage Controlled Temperature CompensatedCrystal Oscillator).The PLLs are located in RF ASICs and controlled via RFBus.Reference oscillatorA 38.4MHz VCTCXO is used as a reference oscillator for the frequency synthesizers.The frequency of the reference oscillator is locked into the frequency of the base station with the help of anAFC voltage, which is generated in BB by DSP and converted by dedicated DAC.RM-132; RM-133Nokia Customer Care System ModulePage 9 –38 COMPANY CONFIDENTIAL Issue 1Copyright © 2006 Nokia. All rights reserved.