HUAWEI TECHNOLOGIES CO., LTD.www.huawei.comHuawei Confidential Security Level:08/12/15 DRFU and DTRU TrainingLiu Qiang (ID: 00133269)RF Enhancement R&D Dept, WHUAWEI TECHNOLOGIES CO., LTD.!age 2Huawei Confidential ContentsIntroduction to RF/IF PrinciplesTest of Key CountersTroubleshootingHUAWEI TECHNOLOGIES CO., LTD.!age 3Huawei Confidential Int"#$ucti#n t# RF%IF !"incip&e'1. RX/TX diagrams for the DRFU and DTRU 2. Introduction to functional modulesHUAWEI TECHNOLOGIES CO., LTD.!age (Huawei Confidential R)%*) Diag"am +#" the DRF, Fi&te" !-...*)1*)2R)/R).!/1!/2Dup&e0+i&te"1Dup&e0+i&te"2I'#&at#"1I'#&at#"2L/1L/2123"i$ a$/*1/*2-!RI1-!RI2!#4e" !#4e"LEDR)2 #ut R)1 #ut R)2 in R)1 inFi&te" !-...IF*)/*).R)/R).!/1 !//!/2 !/.Dup&e0+i&te"1Dup&e0+i&te"2Dup&e0+i&te"1Dup&e0+i&te"2I'#&at#"1I'#&at#"2L/1L/2123"i$ a$!#4e"!/53ac6en$R)5+"#nten$Fi&te" !-...*)1*)2R)/R).!/1!/2Dup&e0+i&te"1Dup&e0+i&te"2I'#&at#"1I'#&at#"2L/1L/2123"i$ a$/*1/*2-!RI1-!RI2!#4e" !#4e"LEDR)2 #ut R)1 #ut R)2 in R)1 inFi&te" !-...IF*)/*).R)/R).!/1 !//!/2 !/.Dup&e0+i&te"1Dup&e0+i&te"2Dup&e0+i&te"1Dup&e0+i&te"2I'#&at#"1I'#&at#"2L/1L/2123"i$ a$!#4e"!/53ac6en$R)5+"#nten$*he DRF, in7#&7e' the RF%IF 'ma&&5'igna& pa"t, p#4e" amp&i+ie" (!/), 3a'e3an$, an$ p#4e" 'upp&28HUAWEI TECHNOLOGIES CO., LTD.!age 9Huawei Confidential HUAWEI TECHNOLOGIES CO., LTD.!age 6Huawei Confidential RX/TX Diagram for the DTRU HUAWEI TECHNOLOGIES CO., LTD.!age :Huawei Confidential HUAWEI TECHNOLOGIES CO., LTD.!age ;Huawei Confidential RF Di++e"ence' .et4een the DRF, an$ the D*R,18 *he DRF, i' integ"ate$ 4ith the -n#i'e amp&i+ie" (L/) an$ $up&e0e"8 *# imp&ement the +uncti#n' #+ the DRF,, the D*R, mu't 3e c#n+igu"e$ 4ith the DD!,828 *he DRF, imp&ement' 'epa"ate an$ c#m3ine$ +uncti#n' th"#ugh "e&a2 '4itching, 4he"ea' the D*R, imp&ement' the'e +uncti#n' th"#ugh '4itche' #n the RF c#a0ia& c#nnect#"8 38 *he DRF, can imp&ement c#m3ine$ ca3inet' th"#ugh '4itche', 4he"ea' the D*R, $#e' n#t imp&ement c#m3ine$ ca3inet'8HUAWEI TECHNOLOGIES CO., LTD.!age 9Huawei Confidential Int"#$ucti#n t# Functi#na& @wa& power $i.i$er. The signal amplitu$e of the mo$ule is >@0 $!m. The central fre8uenc& of DC11800 is @A8% an$ that of =:19 is (signal part. The power of the small>signal part must reach more than >signal part on the test port% &ou can $isconnect the TX channel an$ use an e;ternal en$ up ca#le for test. "n this case% the signal le.el e;cee$s 10 $!m.The possi#le causes for the han$o.er spectrum pro#lem are as followsCa.The linearit& of the 3 ma& cause this pro#lem. "n a$$ition% use the oscilloscope to chec2 whether the gate .oltage wa.eform is normal. "f the gate .oltage wa.eform is a#normal% chec2 the gate .oltage line. The han$o.er spectrum is a#normal. HUAWEI TECHNOLOGIES CO., LTD.!age 39Huawei Confidential The han$o.er spectrum is a#normal. #.The small>signal part ma& cause this pro#lem. Test local oscillator signals to chec2 whether the spurious emission of the phase>loc2e$ source a0ects the mo$ulation spectrum. R e f - 2 0 d B m A t t 5 d B1 A PC L R W RAC e n t e r 9 4 2 . 4 0 0 6 4 1 M H z S p a n 1 M H z 1 0 0 k H z /* R B W 3 k H z*B W 5 0 0 H zS W ! 1 . 1 5 "- 1 2 0- 1 1 0- 1 0 0- 9 0- # 0- $ 0- 6 0- 5 0- 4 0- 3 0- 2 01M a r k e r 1 % ! 1 &- 2 # . 0 9 d B m9 4 2 . 4 0 0 6 4 1 0 2 6 M H z2' e ( t a 2 % ! 1 &- 5 3 . # 0 d B1 9 # . $ 1 $ 9 4 # $ 1 # k H z3' e ( t a 3 % ! 1 &- 6 $ . # 6 d B2 5 6 . 4 1 0 2 5 6 4 1 0 k H z4' e ( t a 4 % ! 1 &- $ 5 . 3 5 d B3 2 # . 5 2 5 6 4 1 0 2 5 k H z'ate) 21.*+,.200#10)44)54c.The han$o.er spectrum of the DTRU or DR*U is teste$ in *F mo$e. "f the test result on the e8uipment is a#normal #ut the manual test result is normal% test the han$o.er spectrum in *F mo$e.HUAWEI TECHNOLOGIES CO., LTD.!age (0Huawei Confidential =rror Bector 9agnitu$e /=B9+ $e)nes the error #etween the signal .ector in a real transmission en.ironment an$ that in an i$eal transmission en.ironment. =B9 an$ fre8uenc&>phase error represent the mo$ulation accurac& in a $i0erent mo$ulation scheme.The mo$ulation scheme of =D:= signals is 8315% an$ the power of TX signals changes in a timeslot. That is% there are #oth the .ector error an$ the magnitu$e error #etween the actual signal .ector an$ the i$eal signal .ector. "n a$$ition% these factors cause the origin $rift on the constellation $iagram. Therefore% =B9 an$ 771 are use$ to represent the mo$ulation accurac& of =D:= signals.The mo$ulation scheme of :915 signals is a special fre8uenc&>shift 2e&ing /*15+ mo$ulation scheme. The signals are mo$ulate$ on the fre8uenc& of the TRX% an$ the power of TX signals remains unchange$ in a timeslot. Therefore% there are onl& the phase error an$ phase change error /fre8uenc& error+ #etween the actual signal .ector an$ the i$eal signal .ector. "n this case% the fre8uenc& error an$ phase error are use$ to represent the mo$ulation accurac& of :915 signals.The =B9 is a#normal. HUAWEI TECHNOLOGIES CO., LTD.!age (1Huawei Confidential The =B9 pro#lem is generall& cause$ #& the 3.,ocation metho$Ca. The most common =B9 pro#lem is that the 771 test .alue is less than (5% which is cause$ #& the poor shiel$ing of the shiel$ co.er. Hou can sol.e this pro#lem #& reinstalling the shiel$ co.er% tightening the screws at 2e& locations /for e;ample% screws near the 3+% or replacing the shiel$ co.er. #. Test high% mi$$le% an$ low fre8uencies manuall&% especiall& the wor2ing fre8uencies of the DR*U teste$ #& the e8uipment. The im#alance #etween high an$ low fre8uencies often occurs on the 3. "n a$$ition% chec2 the power si'e.c .Test the power. "f the power is at least 0.5 $! greater than the theoretical .alue% chec2 the information a#out the power $etection ta#le% for e;ample% the linearit& of the $etection circuit an$ the line loss of the e8uipment.$."f the power is normal% $ecrease the power le.el. "f the =B9 is impro.e$ signi)cantl&% it in$icates that this pro#lem is cause$ #& the linearit& of the 3. e.The signals after spatial coupling are ampli)e$ #& the 3% an$ the =B9 of the small>signal part is a0ecte$. Therefore% when testing the =B9 of the small>signal part% &ou are a$.ise$ to $isconnect #oth the DC>separating capacitor on the TX channel an$ the power suppl& of the 3. :enerall&% the =B9 of the small>signal part is less than 2I or it can reach (.5I in the case of interference. "n this case% the location of the test ca#le relati.e to the 3 must #e consi$ere$.The =B9 is a#normal. HUAWEI TECHNOLOGIES CO., LTD.!age (2Huawei Confidential The recei.e sensiti.it& is a#normal.The sensiti.it& is $etermine$ #& the gain of the RX channel% noise coeJcient% an$ $emo$ulation ratio. The sensiti.it& of the R* channel is $etermine$ #& the gain an$ noise coeJcient. "t is $iJcult to o#ser.e the noise coeJcient.,ocation metho$C 7#ser.e the signal le.els of the input an$ output en$s of each 2e& component on the channel. The e8uipment is teste$ in *F mo$e% an$ therefore &ou must perform the test in *F mo$e when locating the pro#lem. a. Chec2 whether an R* phase>loc2e$ loop alarm is generate$. Dhen the loc2ing time of the R* phase>loc2e$ loop is a#normal% the sensiti.it& ma& #ecome poor. "n this case% the main an$ $i.ersit& sensiti.ities on channelor ! #ecome poor. #. Use the signal source to input signals of a certain le.el /for e;ample% >15 $!m+ to the RX channel% an$ then chec2 whether the input an$ output signal le.els of the lower>le.el 2e& components are a#normal. Chec2 the R* input port of the mi;er% "* $i0erential output port% an$ input an$ output ports of the 1D )lter. "n a$$ition% &ou nee$ to chec2 local oscillator signals when chec2ing the mi;er.c. "f a channel has the poor main or $i.ersit& sensiti.it&% cross the "* $i0erential signals in the channel using a ca#le with the appropriate length. The main an$ $i.ersit& shoul$ not #e crosse$ simultaneousl&K otherwise% the interference occurs. HUAWEI TECHNOLOGIES CO., LTD.!age (3Huawei Confidential 5e& path of the loop#ac2C mi;er insi$e the DB: >L input en$ of the RX channel >L M The le.el of loop#ac2 signals is low% an$ therefore the attenuation .alue insi$e the instrument shoul$ not #e set to a too large .alue. Hou are a$.ise$ to set the attenuation .alue to 0 $!.,ocation metho$Ca. 1en$ a loop#ac2 test comman$ on the !T19. Connect a ca#le from the output port of the RX channel to the spectrum anal&'er an$ then o#ser.e the signal 8ualit&. The normal signal le.el is a#out >