1 / 32

手机射频校准

手机射频校准. 什么是射频校准？. The process of obtaining RF parametric data to be used by the phone for the purpose of compensating for non-linear devices, frequency variations, and temperature variations Output from the calibration process is stored in non-volatile (NV) memory

avent
Download Presentation

手机射频校准

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 手机射频校准

  2. 什么是射频校准？ • The process of obtaining RF parametric data to be used by the phone for the purpose of compensating for non-linear devices, frequency variations, and temperature variations • Output from the calibration process is stored in non-volatile (NV) memory • DMSS uses RF NV items during normal operation to ensure system performance is met.

  3. 射频校准的意义? (1) • Subscriber units have differing RF characteristics. -Some characteristics vary from one unit to the next -Other characteristics vary from one design to the next

  4. 射频校准的意义? (2) • The subscriber unit must estimate the Rx power properly to maximize signal to noise ratios and to provide a basis for Tx power output. • The subscriber unit must transmit at correct Tx power level over its large dynamic range.

  5. 射频校准的意义? (3) • The MSM device and system software combination must “know” the RF characteristics of the particular unit. This information is known as RF calibration data. • Failure to compensate for differing RF characteristics may cause the unit to fail minimum performance specifications.

  6. 射频校准的意义? (4) • Calibration Consideration: - Some NV Items will be static per phone design » Ex: NV_CDMA_ENC_BTF - Other NV items will vary from one phone to the next and need to be calibrated » Ex: NV_CDMA_TX_LIN_MASTER_1

  7. 射频校准的信号流图

  8. 射频校准工位搭建

  9. NV项 • Calibration compensates for nonlinear characteristics, and temperature and frequency variations in the performance of the Tx and Rx path components in a subscriber unit • Output from the calibration process are stored in nonvolatile (NV) memory items in AMSS software • DMSS software loads calibration values into MSM registers or uses them for software processing during normal DMSS operation • NV items can be accessed using raw DIAG commands or using DIAG-based tools, such as the QPST RF Calibration Tool • Some NV items will be static per the hardware design • Other NV items will vary from one unit to the next • Some elements within an NV item can be extrapolated

  10. NV项类型 • Static RF NV Items: Value is determined by design and does not change for the same design. Ex: NV_CDMA_NONBYPASS_TIMER_I • Calculated RF NV Items: Value is calculated based on other parameters of the design configuration and value does not change for a given configuration. Ex: NV_CDMA_LNA_RANGE_RISE_I • Measured RF NV Items: Value is defined by RF calibration process and each device may have a different value. Ex: NV_CDMA_TX_LIN_MASTER_0_I

  11. FTM介绍 • FTM is expandable, allowing customers to build onto the functions for manufacturer-specific testing • FTM is now a part of QPST • Extensive documentation is available for customer reference –80-V4690-25 Rev. B MSM 6250 RF NV Items –CL-93-V5368-1 Rev. C Factory Test Mode WCDMA Commands –CL93-V5370-1 Rev. F Factory Test Mode GSM Commands –80-V5359-1 Rev. E FTM Overview

  12. 运行FTM • Released DMSS can be made to boot up in one of two operating modes – Normal “DMSS” mode with regular cellular operation – FTM mode with no cellular system determination and call-processing • By default, DMSS will power up in normal mode • AMSS software is also capable of switching modes at run-time (no reset required) – To switch from online to FTM, send a “Mode FTM” command to the phone. – To switch from FTM to online, send a “Mode Online” command. • To activate FTM: – Send Off_line command to target – Send Diag Command NV_WRITE and set NV item NV_FTM_I to 1. – Reset target by sending a MODE_RESET command. Target will boot up in FTM mode. Target LCD screen should display “Factory Test Mode” • At this point the unit is ready to receive FTM commands

  13. FTM命令介绍（1） • Bool Set PDM(pdm_id_type type) – This command sets the value of a PDM output, based on PDM_ID such as Tx_Agc_Pdm or Rx_Agc_Pdm • Byte Get ADC(adc_id_type type, word* data = NULL) This command returns the value of the specified analogto- digital converter (ADC) channels. • Word GetCAGC_RX_AGC() – This command returns the 10-bit 2’s complement output of the RX AGC loop • Bool GetSynthLockState() – This command returns the state of the RF synthesizers.

  14. FTM命令介绍（2） • Bool SetCDMAWaveCW(bool on_off) – This command sets the modulation ON/OFF for the uplink waveform. Pass in “true” for CW waveform and “false” for WCDMA uplink waveform • Bool SetChannel(word channel) – This command sets the uplink and downlink channel • Bool SetLNAOffset(byte index, int value) – This command sets the LNA offset register • Bool SetLNARange(lna_range_type range) – This command sets the LNA range state machine to the specified state

  15. FTM命令介绍（3） • Bool SetMode(mode_id_type mode) – This function makes a selection between GSM and WCDMA operating modes. It initializes all of the necessary registers to place the phone in the requested mode • Bool SetPARange(pa_range_type range) – This command sets the PA range state machine to the specified state • Bool SetTxOFF() – This command turns off the phone’s transmit chain including the power amplifier and the MSM Tx clocks • Bool SetTxON() – This command turns on the phone’s transmit chain including the power amplifier and the MSM Tx clock

  16. FTM命令介绍（4） • Word GetCDMAIM2(byte* Idac, byte* Qdac, byte* Trans) – This command returns the optimum IM2 value for the current mode and channel of the mobile. Rx signal input are required to be set before issuing this command or results will not be accurate. The resulting word contains two values: – The most significant byte contains the I value – The middle byte contains the Q value – The least significant byte contains the transconductance value • Bool SetDVGAOffset(word offset) – This function sets the DVGA (Digital VGA) offset register • Word GetDVGAOffset(void) – This function gets the DVGA offset register value

  17. Automatic Gain Control (AGC) • The phone does not use dB and dBm to manage power. • In the embedded software, all power is defined in terms of AGC units –AGC units »AGC is stored as 10-bit number »Range is 210,1024 total units »dB/AGC = Dynamic Range (dB) / 1024 »For Dynamic Range = 85.3 dB • There are 12 AGC units per dB –Both RX and TX use AGC units for all power calculations »E.g. Rx must measure power and determine RX AGC. • »E.g. Tx AGC units are used to calculate transmit power (e.g. max power and access probe step sizes).

  18. RX AGC和dBm的转换 • Given –Min RSSI = -106 dBm –AGC/dB conversion = 12 AGC / 1 dB –dB/AGC conversion = 0.08 dB / 1 AGC

  19. TX AGC和dBm的转换 • Given • –Min MSM Tx linearizer power = -57.3 dBm • –AGC/dB conversion = 12 AGC / 1 dB • –dB/AGC conversion = 0.08 dB / 1 AGC

  20. HDET • Phone looking up HDET to get power: –Upper 25% of the Tx dynamic is used to obtain power vs. HDET curve. –HDET dynamic range = 0.25 * 85.3 =21.33 –HDET dynamic range is divided into 16 segments. –HDET max table power = 28.0 dBm –HDET min table power = 6.67 dBm • HDET offset and span –Offset and span define the range in which the power-limiting algorithm is active –Offset: Lowest HDET value used for power limiting = HDET reading at (max Tx power limit - 6dB) –Span: Highest HDET value used for power limiting = HDET reading at (max Tx power limit + 2dB) - offset

  21. Rx Calibration (1)

  22. Rx Calibration (2)

  23. Rx Calibration- IM2 (3) • IM2 calibration is done to improve reception in certain types of jamming situations. • Improper IM2 calibration may cause the mobile station’s FER to increase in these jamming situations.

  24. Rx Calibration- IM2 (4) • Using a signal generator, place an AM modulated carrier with the following characteristics at the input to the antenna »The frequency of the carrier must be offset from the Rx reference frequency by 5.0 MHz. »Program the modulation tone be sinusoidal and to have a frequency of 20 kHz. »Program the signal generator such that the AM modulation depth is 56 %. »Program the signal strength to be –25 dBm at the antenna’s input. »Check the RSSI using the FTM function Get RX AGC. If the RSSI is saturated (at the extreme limit), adjust the signal’s strength accordingly until the RSSI is no longer saturated. • Call the FTM function Get CDMA IM2. It may take approximately 5 seconds before the function returns a value. • Store the two values in NV_CDMA_IM2_I_VALUE and NV_CDMA_IM2_Q_VALUE.

  25. Rx Calibration (5) • FTM command sequence -1.SET_MODE {FTM} -2.RESET -3.TEST_SET_MODE {PHONE_MODE_CDMA_800} -4.TEST_SET_CHANNEL {CDMA reference=202} -5.Input CDMA waveform at ref. channel and at LNA_FALL1 power. -6.TEST_GET_DVGA_OFFSET -7.TEST_GET_LNA_OFFSET {ID=0} -8.Change input power level to LNA_FALL2. -9.TEST_GET_LNA_OFFSET {ID=1} -10.Change input power level to LNA_FALL3. -11.TEST_GET_LNA_OFFSET {ID=2} -12.Repeat steps 4 through 11 for all 16 channels.

  26. Rx Calibration (6) • Stored in following NV items: NV_CDMA_VGA_GAIN_OFFSET NV_CDMA_VGA_OFFSET_VS_FREQ NV_LNA_RANGE_OFFSET NV_CDMA_LNA_RANGE_OFFSET_VS_FREQ NV_LNA_RANGE_12_OFFSET NV_CDMA_LNA_RANGE_12_OFFSET_VS_FREQ NV_CDMA_LNA_3_OFFSET NV_CDMA_LNA_ 3_OFFSET_VS_FREQ NV_CDMA_LNA_ 4_OFFSET NV_CDMA_LNA_ OFFSET_VS_FREQ NV_CDMA_IM2_I_VALUE NV_CDMA_IM2_Q_VALUE NV_CDMA_IM2_TRANSCONDUCTOR_VALUE

  27. Tx Calibration (1)

  28. Tx Calibration (2) Nonlinear RF characteristics of the Tx AGC amplifier are captured in linearizer tables

  29. Tx Calibration (3) • FTM command sequence • 1.SET_MODE {FTM} • 2.RESET • 3.TEST_SET_MODE {PHONE_MODE_CDMA_800} • 4.TEST_SET_CHANNEL {CDMA reference=202} • 5.TEST_SET_TX_ON • 6.TEST_SET_PA_RANGE {LOW_POWER} • 7.Measure Tx power and use TEST_SET_PDM {Tx_AGC,x} to adjust until the desired Tx power for index 0 is achieved. Record Tx_AGC PDM. • 8.Repeat Step 7 for all other indices from 1 to 36. • 9.TEST_SET_PA_RANGE {HIGH_POWER} • 10.Adjust the Tx power as described in Step 7, and record Tx AGC PDMs and HDET values for all 37 indices.

  30. Tx Calibration (4) • Stored in the following NV items: NV_CDMA_TX_LIN_MASTER0 NV_CDMA_TX_LIN_MASTER1 NV_TX_COMP0 NV_TX_COMP1 NV_HDET_OFF NV_HDET_SPN NV_CDMA_TX_LIM_VS_FREQ NV_CDMA_EXP_HDET_VS_AGC

  31. RF Calibration-硬件设备接口 (1) • GPIB硬件接口 -GPIB接口是一个数字化24脚并行总线，其中16根为TTL并行总线，包括8根双向数据线、5根控制线、3根握手线，另8根为地线和屏蔽线。 -GPIB卡作为计算机与测量仪表之间的桥梁，主要承担着命令、数据的传送功能，计算机通过控制GPIB卡向测试仪表发送控制命令，控制测试仪表执行相应的动作、进行相应的测试；计算机向测试仪表发送数据读取命令，控制测试仪表将测试数据通过GPIB接口送入计算机；

  32. RF Calibration-硬件设备接口 (2) • NI公司提供的常用IEEE488.2函数 -viOpenDefaultRM (ViPSession vi) -viOpen(ViSession vi, …) -viPrintf(ViSession vi, ViString writeFmt, ...) -viQueryf (ViSession vi, …) -viClose(ViObject vi)

More Related