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Issue 2 10/2004 COMPANY CONFIDENTIAL

Nokia Customer Care

NHL-12 Series Transceivers

7 - RF Description &

Troubleshooting

Summary of content (46 pages)

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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care RF Description and Troubleshooting ................................................................ 4 RF key component placement ........................................................................... 4 RF measurement points..................................................................................... 5 Test points .......................................................................................................
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care 1. RF Description and Troubleshooting The RF module performs the necessary high frequency operations of the GSM850/1800/1900 tripleband (EDGE) engine. Both the transmitter and receiver have been implemented by using direct conversion architecture which means that the modulator and demodulator operate at the channel frequency. The core of the RF is an application-specific integrated circuit, Helgo.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting RF circuitry is located on one side of the 8-layer PWB. The possible EMC leakage is prevented by using metal cans.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Test points Table 1: Test points Signal name 8 Reference Signal name Reference VBAT C7020 To Antenna J7100 VR1 C7306 VANT 1 C7102 VR2 C7326 VANT 2 C7101 VR3 C7201 VANT 3 C7100 VR4 C7303 RFBusEna1X R7302 VR5 C7304 RFBusData R7302 VR6 C7302 RFBusClk R7302 VR7 C2230 RESET R7302 VrefRF01 C7311 VCTCXO G7200 RFTemp C2226 Clk to BB C2902 VCO out G7201 RFout 1800/1900 Z7100 VCO VCC C7205 TXA C7313
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care 2. RF Implementation in NHL-12 ■ RF frequency plan 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 baseband modulated signals are directly converted up to the transmission frequency and the received RF signals directly down to the baseband frequency.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care ■ RF power supply configuration Figure 6:Power distribution diagram HELGO LNA GSM1800/ 1900 Issue 2 10/2004 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting 3. Introduction to RF troubleshooting All measurements must be done using a spectrum analyzer with a high-frequency high-impedance passive probe (LO-/reference frequencies and RF power levels) and an oscilloscope with a 10:1 probe (DC-voltages and low frequency signals). The RF section is build around one RF ASIC (HELGO N7300).
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care 4. Receiver Description and Troubleshooting ■ Receiver Each receiver path is a direct conversion linear receiver. From the antenna, the received RF signal is fed to a front end module where a diplexer first divides the signal into three separate paths according to the band of operation: either lower GSM850 or upper GSM1800 or GSM1900 path. Most of the receiver circuitry is included in Helgo.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Receiver characteristics Item Values, GSM850/1800/1900 Type Direct conversion, Linear, FDMA/TDMA LO frequencies 3476...3576 MHz / 3610...3760 MHz/ 3860...3980 MHz Typical 3 dB bandwidth +/- 91 kHz Sensitivity min.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care ■ General instructions for Rx troubleshooting 1. Connect the test jig (MJ-13) to a computer with a DAU-9S cable or to a FPS-8 flash prommer with an XCS-4 modular cable. Make sure that you have PKD-1 dongle connected to the computer’s parallel port. 2. Connect a DC power supply to the module test jig with a PCS-1 cable. 3.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting ■ Troubleshooting charts for receiver Troubleshooting diagram for GSM850 receiver Phone in “Continuous” mode, AGC setting “12”. Apply –90dBm 881.66771MHz signal from generator to antenna connector Yes Oscilloscope at RX_I Signal 700mVpp DC offset 1.35V*** Frequency 67.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Troubleshooting diagram for GSM1800 receiver Phone in “Continuous” mode, AGC setting “12”. Apply –90dBm 1842.86771MHz signal from generator to antenna connector Yes No Oscilloscope at RX_I Signal 140mVpp DC offset 1.35V *** Frequency 67.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Troubleshooting diagram for GSM1900 receiver Phone in “Continuous” mode, AGC setting “12”. 18 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care When measuring with an oscilloscope on "RXI" or "RXQ", the following screens should be seen on a working GSM850, GSM1800 or GSM1900 receiver: Figure 8:Rx I/Q signal, burst mode, input level –90dBm. Figure 8, “Rx I/Q signal, burst mode, input level –90dBm.” : Receiver I or Q burst mode signal (channel 190) measured from test point RXI or RXQ with 881.6671 MHz signal, input level –90dBm at RF-connector.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Figure 9:GSM1900 Rx I or Q signal (trace2), burst mode. Figure 9, “GSM1900 Rx I or Q signal (trace2), burst mode.” : GSM1900 receiver burst mode I or Q signal at ch 661 with input signal 1960.067MHz, level –90 dBm at RF-connector. Trace2: With wider time scaling both monitoring and own Rx bursts are seen, 1st burst (shorter) is monitoring and 2nd burst (longer) is own Rx burst.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Figure 10: Rx I&Q, phase difference 90 deg between signals. Figure 10, “Rx I&Q, phase difference 90 deg between signals.” : Detailed view of GSM850 continuous mode Rx I and Q signals measured from test points RXI and RXQ simultaneously. Used channel 190, input signal 881.6671 MHz, level –90 dBm at antenna port, AGC setting 12. Phase difference should be 90 degrees between Rx I and Q signals at all bands.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting 5. Transmitter Description and Troubleshooting The transmitter consists of two final frequency IQ-modulators and a power amplifier (separate ones for the lower and upper bands), and a power control loop. The IQ-modulators are integrated in Helgo, as well as the operational amplifiers of the power control loop. The two power amplifiers are located in a single module with a power detector.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Figure 11:Power amplifier GSM850 EGSM out GSM850 EGSM in GSM1800/ DCS/ 1900 PCS out GSM1800/ DCS/ 1900 PCS in GSM850 EGSM Power control GSM1800/ 1900 DCS/PCS Power control Power detector Mode ■ RF ASIC Helgo The RF ASIC features include: • Package uBGA108 • Balanced I/Q demodulator and balanced I/Q modulator • Power control operational amplifier, acting as an error amplifier • Balanced signal from VCO, frequencies 3420 to 3980 MHz • I
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting ■ General instructions for Tx troubleshooting For a description of the test setup, refer to the Service Software Section, Service Concept diagram. 1. Connect a test jig to the computer with a DAU-9S cable or to a FPS-8 flash prommer with an XCS-4 modular cable. • Make sure that you have PKD-1 dongle connected to the computer’s parallel port. 2. Connect a DC power supply to module test jig with a PCS-1 cable. 3. Set the DC supply voltage to 4.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Transmitter troubleshooting diagram Figure 12:Transmitter troubleshooting TX Troubleshooting TX OK Yes Check output signal level: +32…+33dBm@836.6MHz(GSM850) +29…+30.5dBm@1747.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Figure 13:Helgo IC troubleshooting Helgo troubleshooting Check with oscilloscope: -TXI/TXQ signals -VR1 = 4.8V and VR2, VR4, VR5, VR6 =2.8V -VrefRF01 = 1.35V -Helgo serial interface -TXP & TXC signals No Baseband troubleshooting OK? Yes Check with RF probe: 4G VCO signal output: -3346.4MHz (GSM850) -3495.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Figure 14:PA and antenna switch troubleshooting PA & ant switch troubleshooting Check with RF probe signal level on PA input >= 0dBm OK? Yes Check with oscilloscope: -VANT1 (GSM850) -VANT2 (GSM1800) -VANT3 (GSM1900) OK? Yes Yes Replace ant. switch No Check with oscilloscope: -VBATT ~4V -VTXB = 2.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Pictures of transmitter signals VPCTRL 850 at GSM850 VPCTRL 1800/1900 at GSM1800 VTXB 850 at GSM850 VTXB 1800/1900 at GSM1800 TXC at GSM850 TXC at GSM1900 28 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care TXP at GSM850 TXP at GSM1900 TX I/Q at GSM850 TX I/Q at GSM1800 VANT1 at GSM850 (TX) VANT3 at GSM1900 (TX) Issue 2 10/2004 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care 6. Additional Information on EDGE Troubleshooting Note! EDGE mode troubleshooting differs slightly from basic GSM troubleshooting. 1. Establish connection to the phone normally (see GSM850/1800/1900 troubleshooting instructions). 2. Select product from the menu: File -> Choose Product -> NHL-12. 3. From the toolbar, set operating mode to “Local”. 4. Activate the RF Controls window from the menu: Testing -> RF Controls.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Figure 15:Transmitter EDGE troubleshooting TX OK TX EDGE Troubleshooting Yes Yes Check output signal level: Check all power levels, OK? +24…+30dBm@897.4MHz(GSM900) +24...+30dBm@836.6MHz(GSM850) +22…+29dBm@1747.8 and 1880MHz +24...30dBm@897.4MHz(GSM900) (GSM1800&1900) +22...+29dBm@1747.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Figure 16:Helgo EDGE troubleshooting Helgo EDGE troubleshooting Check with oscilloscope: -TXI/TXQ signals -VR1 = 4.8V and VR2, VR4, VR5, VR6 = 2.8V -VrefRF01 = 1.35V -Helgo serial interface -TXP & TXC & TXA No Baseband troubleshooting OK? Yes Check with RF probe: 4G VCO signal output: -3346.4MHz(GSM850) -3589.6MHz (GSM900) -3495.6MHz(GSM1800) -4495.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Pictures of EDGE transmitter signals VPECTRL3 at EDGE850 VPECTRL3 at EDGE1900 VTXB 850 at EDGE850 VTXB 1800/1900 at EDGE1900 Mode at EDGE850 Mode at EDGE1900 Issue 2 10/2004 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting TXA at EDGE850 TXA at EDGE1900 TXC at EDGE850 TXC at EDGE1900 TXP at EDGE850 TXP at EDGE1900 36 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Iref 850 at EDGE850 Iref 1800/1900 at EDGE1900 TX I/Q at EDGE850 TX I/Q at EDGE1900 VANT1 at EDGE850 (TX) VANT3 at EDGE1900 (TX) Issue 2 10/2004 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting 7. Synthesizer Description and Troubleshooting One PLL synthesizer is generating all the required frequencies for both Rx and Tx and for all three bands (GSM850/1800/1900). ■ Frequency synthesizers The VCO frequency is locked by a PLL (phase locked loop) into a stable frequency source given by a VCTCXO which is running at 26 MHz.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Table 2: 26 MHz reference oscillator (VCTCXO) Parameter Min Typ Max Unit/ Notes Frequency stability vs. load change (2kohm//10pF +/-10%) -0.3 +0.3 ppm Aging -1.0 +1.0 ppm/ year Control voltage, Vc 0.3 2.3 V Control voltage slope, 0.3V
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Table 3: VCO Parameter Conditions Output power level Min Nom -3.0 Output impedance VSWR Unit dBm 50 ohm 2.0 Phase noise, fo +/- 25 kHz fo +/- 600 kHz fo +/- 1600 kHz fo +/- 3000 kHz fo +/- 20000 kHz -90 -116 -126 -136 -152 dBc/Hz dBc/Hz dBc/Hz dBc/Hz dBc/Hz Pulling figure VSWR=2, any phase -5.0 +5.0 MHz Pushing figure Vcc=2.7+/0.15V -1.5 +1.5 MHz Frequency stability over temperature range Temp=10...+75deg. C -15.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care ■ General instructions for synthesizer troubleshooting Checking synthesizer operation 1. Connect a test jig to the computer with a DAU-9S cable or to a FPS-8 flash prommer with an XCS-4 modular cable. • Make sure that you have a PKD-1 dongle connected to the computer’s parallel port. 2. Connect a DC power supply or FPS-8 to the module test jig with a PCS-1 cable. 3. Set the DC supply voltage to 3.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting Troubleshooting chart for PLL synthesizer Figure 18:Frequency synthesizer troubleshooting Synthesizer troubleshooting Yes *(When 2.5kOhm passive probe is used, correct the measurement by +34 dB Set with RF controls: Active Unti = Rx Operation mode = Continuous Yes Synthesizer OK Check with RF probe: - 4G VCO out signal - 3526.4 MHz (GSM850) - 3685.
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NHL-12 7 - RF Description & Troubleshooting Nokia Customer Care Pictures of synthesizer signals VCTCXO at GSM1900 (RX) Clk to BB at GSM1900 (RX) VCO out at GSM850 (TX) Issue 2 10/2004 COMPANY CONFIDENTIAL Copyright © 2004 Nokia. All Rights Reserved.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting ■ Frequency lists GSM850 CH 44 VCO TX VCO RX CH VCO TX VCO RX CH VCO TX VCO RX 128 824.2 869.2 TX RX 3296.8 3476.8 170 832.6 877.6 TX RX 3330.4 3510.4 212 841.0 886.0 3364.0 3544.0 129 824.4 869.4 3297.6 3477.6 171 832.8 877.8 3331.2 3511.2 213 841.2 886.2 3364.8 3544.8 130 824.6 869.6 3298.4 3478.4 172 833.0 878.0 3332.0 3512.0 214 841.4 886.4 3365.6 3545.6 131 824.8 869.8 3299.2 3479.
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NHL-12 7 - RF Description & Troubleshooting GSM1800 CH 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 TX 1710.2 1710.4 1710.6 1710.8 1711.0 1711.2 1711.4 1711.6 1711.8 1712.0 1712.
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NHL-12 Nokia Customer Care 7 - RF Description & Troubleshooting GSM1900 CH 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 46 TX 1850,2 1850,4 1850,6 1850,8 1851,0 1851,2 1851,4 18