Galaxy H/W Training - GPRS RF Part ASUS RD Division IA Department HW-2 Group Alan Lin 2006/01/23

2 Agenda 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 Function Introduce to GPRS Function

4 GPRS Block Diagram T/R SW PA RF ChipBB Chip PMIC Flash RF Part BB Part PDA Part FFUART Analog IQ Pink :GPRS RF Green : GPRS Base-Band Blue :PDA

5 Transceiver Block Diagram RF : : : : LMSP33QA-321

6 Base-band Block Diagram 3 wire bus for RF transceiver RF Control T/R switch Analog IQ signal Audio RX path Audio TX path SIM

7 Key Parts List

8 Aero 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.

9 Transceiver Functional Block RX SAW RX Loop Universal Baseband Interface (DAC) Power Amp. TX Loop Synthesizer XTAL(DCXO)

10 Receiver Block Diagram Image Reject Low - IF Receiver

11 Low-IF Receiver

12 Image Rejection

13 Aero 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.

14 Transmitter Block Diagram Offset PLL

15 Offset 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

16 DCXO Architecture Frequency adjusted by two variable capacitances - Cdac: coarse tuning - Cafc: fine tuning

Trouble Shooting Trouble Shooting

18 Measurement Equipment Agilent 8960 / CMU200 Power Supply Scope Spectrum Passive Probe with DC Block

19 Base Station Setup Base Station Test Mode Setup

20 Antenna Switch Connector Bottom Side

21 PA & Front-end Top Side T/R Switch High band Matching PA Low band Matching

22 PA & Front-end PALEVEL (VRAMP) High band Matching Low band Matching T/R Switching PA

23 RX Path Top Side T/R Switch RX SAW Transceiver XTAL

24 RX Path RX SAW T/R Switching Transceiver XTAL

25 T/R Control Table

26 Trouble Shooting AFC Fail APC Fail AGC Fail ORFS due to Modulation -200kHz & +400kHz fail Others

27 AFC & TX Testing Nodes A B C D E F H G

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

29 APC 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 Vramp High-band in High-band out

30 APC Fail If TX current is small - Check TXVCO output - Check Vramp - Check PA - Check VBAT T/R SW Low-band in Low-band out Vramp High-band in High-band out

31 AFC & TX Signals

32 26MHz & TXIQ Fig MHz Fig. 1.2 TXIQ

33TXVCO Fig. 1.3 TXVCO DCS Ch700 : MHzFig. 1.4 PA Out DCS Ch700 : MHz

34Vramp Fig. 1.5 Vramp

35 RX Testing Nodes A B E D C F

36 AGC Fail Check antenna switch connector Check T/R switch Check SAW Check RXIQ RX SAW

37 RX Signals

38 26MHz & T/R Switch Out Fig MHzFig. 2.2 EGSM Ch62 : 947.4MHz

39 RX IQ Fig. 2.5 RX IQ