下载文档原格式
RF射频电路设计与调试技巧
射频（Radio Frequency，RF）电路设计与调试是无线通信领域中的重要技术之一，其设计与调试的质量直接影响到整个通信系统的性能。
在实际项目中，经常会遇到一些技术难题，因此需要掌握一些技巧来提高设计与调试的效率和准确性。
首先，设计RF射频电路时，需要考虑的因素有很多，比如频率、功率、带宽、阻抗匹配、噪声等。
在设计过程中，需要根据具体的要求选择合适的器件和元件，如滤波器、放大器、混频器等，来实现整个系统的功能。
此外，还要注意信号的损耗和噪声的影响，以及射频信号的传输和辐射特性。
其次，调试RF射频电路的关键在于准确的测试和分析。
在实际调试中，常用
的工具有频谱分析仪、网络分析仪、示波器等。
通过这些仪器，可以实时监测信号的频谱、波形和幅度，并对电路的性能进行评估。
同时，还可以通过射频仿真软件对设计的电路进行仿真分析，发现问题并优化设计。
此外，还有一些常用的调试技巧可以帮助提高工作效率。
比如，在调试过程中，可以采用“分而治之”的方法，逐步排除可能存在的问题，从而快速定位故障点。
另外，还要注意防止电路中的干扰和串扰，尽量减小电路中的耦合和杂散信号，提高系统的稳定性和抗干扰能力。
总的来说，设计和调试RF射频电路是一项挑战性的工作，需要技术和经验的
积累。
通过不断的学习和实践，掌握一些设计与调试的技巧，可以更好地解决实际问题，提高工作效率，实现设计目标。
希望大家在实际工作中能够运用这些技巧，不断完善自己的射频电路设计与调试能力。
祝大家在无线通信领域取得更好的成果！。
Wifi电路调试及N4010A使用说明高通8909平台采用WCN3610芯片实现Wifi功能，实验室用N4010A对Wifi进行调试和测试。
本文重点介绍：Wifi电路调试及N4010A的使用说明。
Wifi电路说明WCN3610电路框图如下，三路电源、五路控制线、四根IQ进行数据传输、Wifi/BT共用同一路射频收发通路。
Wifi射频部分原理图如下：Wifi发射接收共通路，均需要通过滤波器进行滤波（发射时防止干扰其他频段，接收时避免被其他频段堵塞），然后和GPS（1.57GHz）信号通过合路器一起连接到三合一天线（Wifi/BT/GPS共天线）。
在平台跑通后，基本上Wifi电路的调试就是滤波器输入输出匹配的调试。
原则是在高中低信道上均需要对输出功率和EVM之间做个平衡，以获得最佳的功率和EVM的组合。
Wifi指标说明WCN3610支持802.11b/g/n，实验室N4010A通常仅测试11b/g。
我们测试报告中对11b的最高速率11Mbps和11g的最高速率54Mbps的射频指标进行测试：802.11b的相关规范如下：频率范围：2.4GHz~2.4835GHz (USA& Europe & China & Canada ) 、2.471GHz~2.497GHz (Japan)。
调制方式及信道速率：调制方式信道速率DBPSK 1Mbit/sDQPSK 2Mbit/sCCK 5.5Mbit/sCCK 11Mbit/s发射功率要求：最大发射峰值功率地理区域规范文档1000 mW USA FCC 15.247, IEEE Std C95.1-1999100 mW(EIRP) Europe ETS 300-32810 mW/MHz Japan 无线电设备的MPT管理条例文章49-20100 mW(EIRP) China 信部无[2002]353号发射频谱掩膜：频率区域频率范围掩模限值<-30dBrA fc-22MHz<f<fc-11MHzfc+11MHz < f< fc+22MHzB f<fc-22MHz<-50dBrf>fc+22MHz频率误差：发射信号频率和相应信道中心频率的误差范围最大容限为±20ppm码片误差：PN码码片时钟频率容限应小于±20ppm上升下降沿发射加电时从最大功率的10%达到90%的时间应不大于2us；发射掉电时从最大功率的90%达到10%的时间应不大于2us。
1. 什么是RF？答：RF 即Radio frequency 射频，主要包括无线收发信机。
2. 当今世界的手机频率各是多少（CDMA，GSM、市话通、小灵通、模拟手机等）？答：EGSM RX: 925-960MHz, TX:880-915MHz；CDMA cellular(IS-95)RX: 869-894MHz, TX:824-849MHz。
3. 从事手机Rf工作没多久的新手，应怎样提高？答：首先应该对RF系统(如功能性)有个系统的认识，然后可以选择一些芯片组，研究一个它们之间的连通性(connectivities among them)。
4. RF仿真软件在手机设计调试中的作用是什么？答：其目的是在实施设计之前，让设计者对将要设计的产品有一些认识。
5. 在设计手机的PCB时的基本原则是什么？答：基本原则是使EMC最小化。
6. 手机的硬件构成有RF/ABB/DBB/MCU/PMU，这里的ABB、DBB和PMU等各代表何意？答：ABB是Analog BaseBand，DBB是Ditital Baseband，MCU往往包括在DBB芯片中。
PMU是Power Management Unit,现在有的手机PMU和ABB在一个芯片上面。
将来这些芯片(RF,ABB,DBB,MCU,PMU)都会集成到一个芯片上以节省成本和体积。
7. DSP和MCU各自主要完成什么样的功能？二者有何区别？答：其实MCU和DSP都是处理器，理论上没有太大的不同。
但是在实际系统中，基于效率的考虑，一般是DSP处理各种算法，如信道编解码，加密等，而MCU处理信令和与大部分硬件外设（如LCD等）通信。
8. 刚开始从事RF前段设计的新手要注意些什么？答：首先，可以选择一个RF专题，比如PLL，并学习一些基本理论，然后开始设计一些简单电路，只有在调试中才能获得一些经验，有助加深理解。
9. 推荐RF仿真软件及其特点？答：Agilent ADS仿真软件作RF仿真。
WARNINGIF “FAIL” APPEARS ON THE DISPLAY, THECALIBRATION REQUIRED LED (LEFTCOLUMN) REMAINS LIT, OR THECALIBRATED LED (RIGHT COLUMN) DOESNOT LIGHT, THE CALIBRATION PROCESSDID NOT COMPLETE. SHOULD THISHAPPEN, CYCLE THE UNIT POWER ANDTHEN REPEAT STEP 2 ABOVE. IF “FAIL”APPEARS AGAIN, FURTHER TROUBLE-SHOOTING IS REQUIRED.3.Remove the test shunt. The RX Occupancy LED shouldlight. If the RX Occupancy LED fails to light, thecalibration process has failed (refer to the WARNINGabove). Inspect all equipment and connections andrepeat steps 1 & 2. If the calibration fails again,further troubleshooting is required.4.The RX Occupancy LED should light once the testshunt has been removed. Proceed to Receiver andTransceiver Checkout Procedures, Section 7.5.1. Receiver and Transceiver Checkout Procedures1.Scroll down the Main Menu of the Receiver untilINFO appears on the display.2.Momentarily press the MENU Button and release it.“+RX SIG LVL =” appears on the Display.3.Take note of RX SIG LVL. This is the normal receivesignal value. Verify the RX SIG LVL value is >300. Ifnot, set TX LVL to High and perform calibration andcheckout procedures again. If the value remainsbelow 300 after selecting TX LVL=High, select a lowerfrequency where RX SIG LVL value is >300.4.In the WSS containing the transmitter, remove thetransmitter’s signal to the track by disconnecting atransmitter lead from the track surge equipment.5.With the corresponding transmitter disabled, observethe RX SIG LVL. If RX SIG LVL is greater than 20, anunintended signal of like frequency may be present.WARNINGDO NOT PROCEED TO STEP 6 ANDBEYOND UNTIL THE UNINTENDED SIGNALOF LIKE FREQUENCY IS NO LONGERPRESENT (THIS MAY REQUIRE AFREQUENCY CHANGE TO AVOIDUNINTENDED HARMONICS.) THISCONDITION MUST BE RESOLVED.6.Verify that the RX LED found in the Occupancyportion of the face of the unit is de-energized. If theLED remains lit, troubleshoot the unit.7.Restore the Transmitter signal to the circuit byreconnecting the lead in the transmitter’s track surgeequipment.8.Verify that the RX LED found in the Occupancyportion of the face of the unit energizes. If the LEDsfail to light, troubleshoot the unit, re-calibrate, andperform Steps 1 - 7 again.9.Verify proper operation of the track circuitequipment before placing in service in accordancewith railroad or agency procedures and applicableFRA rules.10.Verify proper PSO 4000 operation by observing trainmoves, per railroad or agency policy.11.The system is now ready for operation.NOTEIn the text on this side of the document andon the drawing on the reverse side of thedocument, all references to Section numbersare those section numbers found within theSiemens Phase Shift Overlay 4000 (PSO 4000)Installation and Instruction Manual, SIG-00-07-06.QUICK REFERENCE GUIDEINSTALL PSO 4000TRANSMITTER/RECIEVER MODULESDocument Number SIG-QG-10-03Version A.1The following procedure should be used when installingPhase Shift Overlay 4000 (PSO 4000) Track Circuits utilizingPSO 4000 Transmitter, 7A471 and PSO Receiver, 7A473.WARNINGVERIFY THAT THE PSO 4000TRANSMITTER’S AND RECEIVER’SSOFTWARE, FREQUENCY, AND ADDRESSFORMATS ARE AS SPECIFIED BY THERAILROAD’S OR AGENCY’S APPROVEDWIRING OR INSTALLATION DIAGRAM.FAILURE TO DO SO MAY LEAD TOINCORRECT OR UNSAFE OPERATION OFTHE TRACK CIRCUIT.IF ANY RECEIVER IS CALIBRATED IN POORBALLAST CONDITIONS, IT MUST BE RE-CALIBRATED WHEN BALLAST CONDITIONSIMPROVE.FAILURE TO FOLLOW THE RAILROAD’S ORAGENCY’S APPROVED WIRING ORINSTALLATION GUIDELINES REGARDINGRECEIVER SETTINGS AND CALIBRATIONMAY LEAD TO POSSIBLE UNSAFEOPERATION OF THE TRACK CIRCUIT.AFTER CALIBRATION, VERIFY THAT THETRACK CIRCUIT DE-ENERGIZES WHEN THETRACK CIRCUIT IS SHUNTED WITH THEAPPROPRIATE CALIBRATION RESISTANCE(0.06, 0.2, 0.3, 0.4, OR 0.5 OHMS). FAILURETO DO SO MAY LEAD TO INCORRECT ORUNSAFE OPERATION OF THE TRACKCIRCUIT.FOLLOWING INSTALLATION OR AFTERANY RECEIVER MENU CHANGES HAVEBEEN MADE, RECALIBRATE THE RECEIVERAND TEST FOR PROPER OPERATION PERTHE REQUIREMENTS SPECIFIED IN TABLE7-2 AND TABLE 7-3 OF SIG-00-07-06, PSO4000 I & I MANUAL.Perform the following steps to install the PSO 4000 units:1.Install and connect all PSO equipment in the WaysideSignaling Station (WSS) per the railroad’s or agency’sapproved wiring or installation diagram.2.Connect all required wiring per the railroad’s oragency’s approved wiring or installation diagram.3.Prior to beginning programming, verify LEDfunctionality using the *CHECK LED portion of theTEST menu per Section 5.2.7.2. If any LED fails to lightfollowing test, replace the unit.4.Program each unit by performing Set to Default. Thenproceed through the setup (SETP) menu to programeach unit per the railroad’s or agency’s approvedwritten instructions.With each unit properly installed and programmed perwritten instructions, calibrate the receiver (RX) as follows:1.When the track ballast is good, connect a track testshunt (hardwire, 0.06-ohm, 0.2-ohm, or as required)across the track at the receiver track connections.When the ballast is poor, connect the shunt acrossthe track at a point 30 feet beyond the receiver trackconnections. Verify solid connections of the shunt toeach rail.2.Scroll down the Main Menu until CAL appears on thedisplay. Then:•Press the MENU Button for two (2) seconds untilRX CAL appears.•Hold the MENU Button down until the release(REL) message appears. Release the MENU Buttonimmediately once the release (REL) messageappears.•As soon as the MENU button is released, thearmed (ARMD) message appears. Immediatelypress and release the MENU Button as soon asthe ARMD message appears. This starts thecalibration process. If the MENU Button is notpressed within two (2) seconds, the calibrationprocess cancels and the calibration process mustbe restarted.•*RX CAL flashes during the calibration process.•PASS or FAIL appears for two (2) seconds whencalibration is complete. When PASS appears,continue to Step 3. If FAIL appears, theCALIBRATION REQUIRED LED remains lit-2--8--7- Copyright © 2010-2014 SiemensAll Rights ReservedPSO 4000 TRANSMITTER, 7A471PSO 4000 RECEIVER, 7A473 Array-3- -4- -5- -6-。
