galaxy h/w training - gprs rf part asus rd division ia department hw-2 group alan lin 2006/01/23

Galaxy H/W TrainingGalaxy H/W Training- GPRS RF Part- GPRS RF Part

ASUS RD DivisionASUS RD DivisionIA Department HW-2 GroupIA Department HW-2 GroupAlan LinAlan Lin2006/01/232006/01/23

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AgendaAgenda• Introduce to GPRS Function

- Block Diagram- Key Parts List- Aero II Architecture Highlights- Transmitter- Receiver

• Trouble Shooting- Ckt. & Location- AFC- APC- AGC

Introduce to GPRS FunctionIntroduce to GPRS Function

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GPRS Block DiagramGPRS Block Diagram

T/R SW

PA

RF Chip BB Chip

PMIC

Flash

RF Part

BB Part

PDA Part

FFUART

Analog IQ

Pink : GPRS RFGreen : GPRS Base-BandBlue : PDA

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Transceiver Block DiagramTransceiver Block Diagram

RF3166

850: 856441

900: 856387

1800: 856409

1900: 856417

LMSP33QA-321

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Base-band Block DiagramBase-band Block Diagram

3 wire bus for RF transceiver

RF Control T/R switch

Analog IQ signal

Audio RX path

Audio TX path

SIM

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Key Parts ListKey Parts List

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Aero II RX HighlightsAero II RX Highlights• Low IF architecture strengths (200kHz IF)

– Has advantages of Super-Heterodyne architectures :– DC Offsets are located outside the band of interest.– IP2 (AM Suppression) requirements are relaxed.– LO Self Mixing is not a problem.

– Has advantages of Direct Conversion architectures :– No IF SAW Filter required – Image Rejection

requirements are simplified.– Single analog down-conversion stage.– IF Analog Signal Processing is at a low frequency.

– Digital IF signal processing.

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Transceiver Functional Block Transceiver Functional Block RX SAW RX Loop

Universal Baseband Interface

(DAC)

Power Amp.

TX Loop

SynthesizerXTAL(DCXO)

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Receiver Block DiagramReceiver Block Diagram

Image Reject

Low - IF Receiver

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Low-IF ReceiverLow-IF Receiver

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Image RejectionImage Rejection

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Aero II TX HighlightsAero II TX Highlights

• Offset PLL architecture– Band Pass Noise Transfer Function attenuates noise in

RX band.– TXVCO is a constant-envelope signal that reduces the

problem of spectral spreading caused by non-linearity in the PA.

– Eliminates need for TX SAW Filter.

• TX transmit out buffer– Helps eliminate spurs and pulling issues.

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Transmitter Block DiagramTransmitter Block Diagram

Offset PLL

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Offset PLLOffset PLL- The OPLL acts as a tracking band-pass filter tuned to the

desired channel frequency. - The important difference between a PLL and the OPLL is

that the frequency modulation of the reference input is

reproduced at the output of the Tx-VCO without scaling

• Advantage - Low noise floor and spurs - Pulling of the transmit VCO is reduced -Truly constant envelope Output from VCO

• Disadvantage - Only possible with constant

envelope modulation scheme

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DCXO ArchitectureDCXO ArchitectureFrequency adjusted by two variable capacitances

- Cdac: coarse tuning

- Cafc: fine tuning

Trouble ShootingTrouble Shooting

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Measurement EquipmentMeasurement Equipment

• Agilent 8960 / CMU200

• Power Supply

• Scope

• Spectrum

• Passive Probe with DC Block

Spectrum Analyzer

I Q RF

GSM tester

Phone Tool

OscilloscopeDUT

Data cable

RF adaptor

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Base Station SetupBase Station Setup

• Base Station Test Mode Setup

GSM850 EGSM DCS PCSMode BCH + TCH BCH + TCH BCH + TCH BCH + TCH

BS Power -60dBm, -20dBm -60dBm, -20dBm -60dBm, -20dBm -60dBm, -20dBmBCH 190 62 700 661TCH 190 62 700 661

TX PCL 5, 19 5, 19 0, 15 0, 15

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Antenna Switch ConnectorAntenna Switch Connector

Antenna Switch Connector

Bottom Side

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PA & Front-endPA & Front-endTop Side

T/R Switch

High band Matching

PA

Low band Matching

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PA & Front-endPA & Front-end

PALEVEL (VRAMP)

High bandMatching

Low bandMatching

T/R Switching

PA

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RX PathRX PathTop Side

T/R Switch

RX SAW

Transceiver

XTAL

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RX PathRX Path

RX SAW

RX SAWT/R Switching

Transceiver

XTAL

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T/R Control TableT/R Control Table

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Trouble ShootingTrouble Shooting

• AFC Fail• APC Fail• AGC Fail• ORFS due to Modulation Fail

@ -200kHz & +400kHz fail• Others

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AFC & TX Testing NodesAFC & TX Testing NodesA

B

CD

EF

H

G

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AFC FailAFC Fail• Check antenna switch connector• Check Vramp & PA output power• Check 26MHz output

PA

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APC FailAPC Fail• If TX current is right

- Check antenna switch connector - Check T/R switch- Check PA matching circuit

T/R SW

Low-band in

Low-band out

VrampHigh-band in

High-band out

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APC FailAPC Fail• If TX current is small

- Check TXVCO output- Check Vramp- Check PA- Check VBAT

T/R SW

Low-band in

Low-band out

VrampHigh-band in

High-band out

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AFC & TX SignalsAFC & TX Signals

Node Description Value Fig.A XOUT at C957 26MHz, 1.6V 1.1B TXIQ 4.6ms, 1.2V(max) 1.2C TXVCO at C947(GSM850/EGSM) PCL : 19, 902.4MHz ref. 1.3D TXVCO at C944 (DCS/PCS) PCL : 15, 1747.8MHz 1.3E Power at T/RSW(C930) Low-band in PCL : 19, 902.4MHz ref. 1.4F Power at T/RSW(C933) High-band in PCL : 15, 1747.8MHz 1.4

G Power at C946PCL : 19, 902.4MHzPCL : 15, 1747.8MHz

1.4

H VrampEGSM : 1.3V (PCL5), 0.3V (PCL19)DCS : 1.28V (PCL0), 0.3V (PCL15) 1.5

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26MHz & TXIQ26MHz & TXIQ

Fig. 1.1 26MHz

Fig. 1.2 TXIQ

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TXVCOTXVCO

Fig. 1.3 TXVCO DCS Ch700 : 1747.8MHz

Fig. 1.4 PA Out DCS Ch700 : 1747.8MHz

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Vramp Vramp

Fig. 1.5 Vramp

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RX Testing NodesRX Testing Nodes

A

BE

D

C

F

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AGC FailAGC Fail• Check antenna switch connector• Check T/R switch• Check SAW• Check RXIQ

RX SAW

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RX SignalsRX Signals

Node Description Value Fig.A XOUT at C957 26MHz, 1.6V 2.1B Power at C946 EGSM Ch62 : 947.4MHz, BS: -20dBm ref. 2.2C Power at EGSM SAW out EGSM Ch62 : 947.4MHz, BS: -20dBm 2.2D Power at DCS SAW out DCS Ch700 : 1842.8MHz, BS: -20dBm ref.2.2E Power at PCS SAW out PCS Ch661 : 1960MHz, BS: -20dBm ref.2.2F RXIQ EGSM Ch62 : 947.4MHz, BS: -20dBm 2.3

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26MHz & T/R Switch Out26MHz & T/R Switch Out

Fig. 2.1 26MHz Fig. 2.2 EGSM Ch62 : 947.4MHz

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RX IQRX IQ

Fig. 2.5 RX IQ