A sib txawv attenuatoryog ib qho passive lossis nquag RF / microwave tivthaiv tsim los txo cov teeb liab amplitude los ntawm tus nqi tswj tau thaum tswj hwm qhov kev sib tw ua tau zoo thoob plaws nws cov kev ua haujlwm bandwidth. Tsis zoo li cov attenuators ruaj khov, uas muab ib qho kev txiav txim siab qhov kev poob qis, cov attenuators kuj tuaj yeem hloov kho -txawm li cas los xij lossis tsis sib cais - ntawm cov qib attenuation feem ntau los ntawm zero -zero mus rau 30 dB lossis tshaj, nyob ntawm topology thiab daim ntawv thov yuav tsum tau ua. Cov cuab yeej pom cov ntawv thov tseem ceeb hauv kev tswj tsis siv neeg nce lub voj voog, kev tswj hwm lub zog xa hluav taws xob, txais cov khoom siv hluav taws xob ntau ntxiv, thiab ntsuas ntsuas qhov ntsuas qhov ntsuas qhov tseeb yog qhov tseem ceeb.
Vim li cas kuv thiaj tsis tso siab rau Spec Sheets
Kuv yuav ua ncaj ncees: thawj qhov sib txawv ntawm qhov attenuator kuv spec'd rau hauv tus tsim yog kev puas tsuaj. Tsis yog vim qhov tsis zoo -cov ntaub ntawv saib zoo meej. 0.5 dB cov kauj ruam, 31.5 dB ntau, DC rau 4 GHz. Dab tsi cov ntaub ntawv tsis tau hais txog yog qhov kev hloov pauv hloov pauv ntawm qhov kub thiab txias. Peb tab tom tsim ib chav nyob sab nraum zoov rau lub wireless backhaul system. Kev ntsuam xyuas lub caij ntuj sov mus zoo. Tuaj Lub Ib Hlis Ntuj hauv Minnesota, qhov khoom yog 1.8 dB tawm ntawm max attenuation. Lub AGC voj mus rau txiv ntseej sim los them nyiaj.
Zaj lus qhia raug nqi peb lub rooj tsavxwm thiab rau lub lis piam. Tam sim no kuv xyuas peb yam ua ntej kuv txawm saib ntawm qhov attenuation range:
Insertion poob ntawm yam tsawg kawg nkaus attenuation xeev. Qhov no yog koj lub hauv paus nplua nuj-koj tau them txhua lub sijhawm.
Insertion poob delta hla tag nrho qhov kub thiab txias. Muab faus rau hauv nplooj 14 ntawm daim ntawv teev cov ntaub ntawv, feem ntau.
VSWR ntawmtag nrhoattenuation hais, tsis yog ib qho uas lawv cherry - xaiv rau nplooj ntawv pem hauv ntej.
Txhua yam yog qhov thib ob.
Tus PIN Diode: Ua Haujlwm Nrog Quirks
Feem ntau RF engineers ncav cuag tus PIN diode attenuators ua ntej, thiab yog vim li cas. Lub physics yog elegant: txhaj tam sim no mus rau hauv lub intrinsic cheeb tsam, conductivity nce, RF kuj poob. Rov qab qhov kev tsis ncaj ncees thiab koj tau txais siab impedance. Cov hlua ob peb ntawm cov no hauv ib lub pi lossis tee network nrog kev sib raug zoo, thiab koj tau txais kev hloov pauv tsis tu ncua tswj los ntawm DC voltage lossis tam sim no.
Qhov ntau zaus yog tiag tiag impressive. DC rau 40 GHz yog ua tiav nrog cov qauv zoo. Qee qhov tshwj xeeb thawb dhau 50 GHz. Lub Skyworks SKY12347-362LF, uas kuv tau siv nyob rau hauv tej zaum ib lub kaum os tsim, npog DC rau 6 GHz nrog txog 32 dB ntawm ntau yam. Yam khoom. Tsis zoo siab, tab sis ruaj.
Nov yog qhov lawv tsis qhia koj hauv daim ntawv thov: PIN diodes muaj lub cim xeeb ntawm cov zaus tsawg. Hauv qab no txog 10 MHz, cov nqi khaws cia hauv cheeb tsam hauv cheeb tsam tsis meej txaus ntawm RF cycles, thiab koj qhov attenuation dhau los ua teeb liab - theem nyob ntawm. Kuv tau pom thib peb - xaj distortion dhia 15 dB hauv tus qauv tsim uas yuav tsum ua 1 MHz txog 2 GHz. Qhov kev txhim kho tau ntxiv qhov siab -pass lim ntawm cov tswv yim- uas tus kws kes duab vajtse tsis zoo siab txog.
Kub coefficient yog lwm yam gotcha. Tam sim no - tswj tus PIN attenuators drift vim hais tias lub diode tsis kam-vs- nkhaus tam sim no hloov nrog kub. Voltage-tswj versions zoo dua me ntsis tab sis tsis tiv thaiv kab mob. Cov peev nyiaj 0.02-0.05 dB /℃rau kev npaj. Hauv daim ntawv thov kev ntsuas qhov tseeb, qhov ntawd tsis tsim nyog.
Digital Step Attenuators
Tsi txawv kiag li. DSAs hloov ntawm ntu ntu ntu ntu siv FET lossis MEMS hloov pauv. Koj xa cov lus sib txuas lossis cov lus digital, thiab ib feem xaiv qhov kev sib txuas ntawm cov ntaub ntawv tiv thaiv nyob rau hauv txoj kev teeb liab.
Qhov zoo: Repeatability yog qhov tshwj xeeb. Lub xeev 01101 muab rau koj tib yam attenuation hnub no, tag kis, thiab lwm xyoo. Monotonicity yog guaranteed los ntawm kev tsim-txhua me ntsis ntxiv nws qhov kev nce ntxiv. Hloov ceev ntawm nanoseconds (GaAs FET) mus rau microseconds (MEMS), ceev txaus rau TDMA tawg hwj chim tswj.
Qhov tsis zoo: Koj nyob nraum daig nrog cov kauj ruam tsis sib xws. A 6-ntsis DSA muab rau koj 0.5 dB daws teeb meem, uas suab zoo kom txog thaum koj xav tau 7.3 dB thiab yuav tsum xaiv ntawm 7.0 thiab 7.5. Hauv AGC lub voj voog, qhov quantization no tsim cov voj voog txwv. Lub voj yos hav zoov ntawm ob lub xeev mus ib txhis, tsis txhob nyob. Kuv tau "kua" qhov no los ntawm kev ntxiv me me -ntau yam analog VVA tom qab DSA-crude, tab sis nws ua haujlwm.
Dab tuag: glitches thaum hloov me ntsis. Thaum DSA hloov ntawm 01111 (15.5 dB) mus rau 10000 (16 dB), muaj ib lub sijhawm -tej zaum 5 ns, tej zaum 50 ns- qhov twg cov keyboards sab hauv yog nruab nrab ntawm lub xeev thiab qhov attenuation mus rau qhov chaw tsis tau txhais. Feem ntau qis dua qhov kawg ntawm qhov kawg, txhais tau hais tias lub hwj chim spike hits koj downstream amplifier. PE43711 los ntawm pSemi tuav qhov no zoo dua li feem ntau nrog "glitch-tsawg" architecture, tab sis nws tsis yog khawv koob. Tseem muaj lub zog hloov pauv.
Cov khoom, LSBs, thiab Vim li cas 7-ntsis Parts muaj
6-ntsis attenuator nrog 0.5 dB LSB muab 31.5 dB ntau. Cov qauv zoo nkauj.
Yog li vim li cas ho muaj 7-ntsis seem? Ob qho laj thawj. Ua ntej, kev daws teeb meem zoo dua: 0.25 dB cov kauj ruam tso cai rau koj txiav cov kab ke kom tau txais txiaj ntsig ntau dua. Thib ob-thiab qhov no tsis tshua pom tseeb- cov khoom siv ntxiv tuaj yeem siv rau kev rov ua dua. Qee lub tuam txhab tso cai rau koj xaiv ntawm kev siv tag nrho 7 khoom rau 0.25 dB cov kauj ruam lossis siv 6 khoom rau 0.5 dB cov kauj ruam nrog rau 7 ntsis raws li "zoo trim" uas offsets tag nrho nkhaus. Yooj yim rau kev them nyiaj ib feem- rau-ib feem variation hauv ntau lawm.
Peregrine (tam sim no pSemi) pioneer tus txheej txheem UltraCMOS uas ua rau siab -kev ua tau zoo silicon DSAs siv tau. Ua ntej ntawd, yog tias koj xav tau bandwidth loj koj tab tom yuav GaAs, uas txhais tau tias $$$ thiab 5V khoom siv. PE4312 thiab nws cov xeeb ntxwv coj 50-ohm DSAs rau 3.3V CMOS av. Hloov kev lag luam ntawm ntau tus qauv tsim.
MEMS: Kev cog lus thiab Tos
Microelectromechanical systems tau cog lus tias yuav hloov pauv RF attenuation. Cov keyboards me me, qhov tseem ceeb zoo thaum kaw, qhov tseem ceeb qhib thaum qhib. Tsis muaj semiconductor parasitics. Ohmic kev sib cuag.
Txoj kev xav tuav. MEMS attenuators ua tiav qhov poob thiab linearity uas silicon kov tsis tau. Lub Analog Devices ADRF5720 ua haujlwm rau 40 GHz nrog zoo li 1.5 dB ntxig poob. Sim qhov ntawd nrog FET hloov.
Tab sis -thiab qhov no yog qhov loj tab sis - kev ntseeg tau tseem tsis txaus ntseeg. MEMS hloov lub cev txav mus los. Cov khoom txav txav mus los. Cov neeg tsim khoom thov ntau lab lub voj voog, thiab nyob rau hauv cov xwm txheej zoo li qub lawv yuav tau txais lawv. Nyob rau hauv ib daim ntawv thov nrog thermal cycling, av noo, vibration? Kuv tsis ntseeg. Kuv tau pom raws nraim ib qho MEMS attenuator nyob rau hauv ib qho kev tsim khoom uas kuv tau ua haujlwm rau, thiab qhov ntawd yog nyob rau hauv qhov ntsuas ntsuas qhov twg tus nqi hloov pauv yog qee zaum ob peb zaug hauv ib ob. Rau qhov chaw nres tsheb hauv xov tooj ntawm tes ua ntau txhiab lub zog hloov pauv ib ob ... nug kuv dua hauv tsib xyoos.
Kuj tseem muaj teeb meem ntim. MEMS cov cuab yeej xav tau kev sib khi los yog cov huab cua ntub nkag mus rau hauv thiab cov khoom corrode lossis stick. Cov pob Hermetic raug nqi nyiaj. Tag nrho cov lus pom zoo pib wobble thaum koj "$ 15 MEMS tuag" los ntawm "$ 8 hermetic pob" nrog "$ 12 tus nqi sib dhos."
Mechanical Attenuators: Tsis Tau Tuag
Mus rau ib qho chaw kuaj RF thiab koj yuav pom cov tshuab ntsuas hluav taws xob hauv lub tshuab ntsuas ntsuas. Cov tsiaj nyaum waveguide no- lub cev tig daim npav tiv thaiv kom hloov pauv lub teeb liab ntau npaum li cas nws cuam tshuam - muab qhov tseeb uas cov hluav taws xob attenuators tawm tsam kom phim.
Weinschel 953 series. Hewlett-Packard 355C/D (yog, HP, tsis Agilent lossis Keysight-cov khoom no yog qhov qub thiab tseem ua haujlwm). Flann Microwave's precision waveguide units. Lawv hnyav, qeeb, kim, thiab ntseeg tau kiag li. Thaum koj xav tau 40 dB siv raug rau ± 0.1 dB los ntawm 18 txog 26.5 GHz, koj tsis ncav cuag lub semiconductor.
Rau kev siv lub rooj ntev zaum, phau ntawv qhia kauj ruam attenuators nrog nias- nres dials tseem ceeb heev. Ib qho qub Kay 1/839 tuaj yeem muaj rau $ 50 ntawm eBay thiab muab 1 dB cov kauj ruam mus rau 79 dB nrog kev sib raug zoo dua li feem ntau DSAs. Cov kev sib txuas sib txuas ntxiv poob koj yuav xav tau calibrate tawm, tab sis rau kev sim ceev, lawv zoo meej.
Kuv khaws JFW 50R-142 hauv kuv lub rooj tub rau khoom. Tsau 50-ohm coaxial, ntsuas DC-2 GHz, qib ntawm 0 txog 110 dB hauv 1 dB increments. Cov keyboards yog qhov tseeb precision resistor tes hauj lwm, tsis yog semiconductors. Nws yog tsim zoo li lub tank thiab yuav outlast kuv.
Optical Variable Attenuators (VOAs)
Lub ntiaj teb txawv. Nyob rau hauv fiber systems, attenuation yog tswj ntawm optical txheej, thiab cov mechanisms yog fascinating.
MEMS-raws li VOAssiv daim iav tilting. Lub teeb los ntawm lub input fiber, hits daim iav, reflects mus rau cov zis fiber. Tilt daim iav me ntsis thiab qee lub teeb tsis nco qab cov ntsiab lus tso tawm. Tilt nws ntau, ntau lub teeb nco. Analog tswj, tsim nyog ceev, zoo heev repeatability. Lub DiCon MEMS VOA yog qhov tseem ceeb ntawm kev lag luam tus qauv rau kaum xyoo.
Liquid Crystal VOAssiv polarization. Cov kua siv lead ua kua rotates lub xeev polarization ntawm dhau lub teeb; lub polarizer ces attenuates raws li lub kaum sab xis tig. Tsis muaj qhov txav txav ib yam. qeeb dua MEMS, tab sis mechanically mos mos.
Tseem muajsib txawv fiber ntau Bragg gratingmus kom ze thiabelectronically - tswj kev nqusnyob rau hauv tshwj xeeb fibers, tab sis cov no yog niche. Cov xov tooj hauv xov tooj cua feem ntau koj yuav ntsib yog MEMS lossis LC.
Insertion poob tseem ceeb heev ntawm no vim hais tias koj nyob nraum feem ntau nyob rau hauv ib tug saw ntawm amplified spans. Txhua 0.5 dB koj pov tseg hauv VOA yog 0.5 dB ntawm OSNR koj yuav tsis tau rov qab. Qhov zoo MEMS VOAs ua tiav IL hauv qab 0.8 dB; pheej yig ntaus 1.5 dB los yog phem dua.
Cov Lus Qhia Xaiv Tswv Yim
Ob peb yam kuv xav kom ib tug neeg tau hais rau kuv ua ntej:
Kev sib piv attenuators rau qhov system impedance tsis yog xaiv tau.
Yog lawm, koj DSA yog "tso rau 50 ohms." Tab sis yog tias koj lub rooj tsav xwm cov kab sib kis tau tiag tiag yog 52 ohms vim tias koj cov khoom sib dhos tau tawm hauv - lub hom phiaj, koj yuav pom ripple hauv S21 hla zaus uas yuav ua rau koj vwm thaum lub sijhawm ua cim. Qhov no tsis yog lub attenuator qhov txhaum.
01
Lub zog tuav specs xav tias zoo meej heatsinking.
Qhov kev ntsuam xyuas "1W max input" tau ntsuas nrog lub rooj ntsuas ntsuas bolted rau ib qho txhuas thaiv. Ntawm koj lub PCB tiag tiag nrog 1 oz tooj liab thiab tsis muaj thermal vias? Tej zaum koj muaj kev nyab xeeb rau 0.4W. Tej zaum.
02
Tswj interface tseem ceeb tshaj qhov koj xav.
Ib qho piv txwv -interface DSA xav tau 6-7 GPIOs. Yog tias koj lub microcontroller yog GPIO- txwv tsis pub, tam sim no koj tab tom ntxiv cov npe hloov pauv lossis I²C nthuav dav. Serial-interface DSAs zam qhov no tab sis ntxiv latency. Nyob rau hauv lub voj voog AGC ceev, qhov latency yuav tseem ceeb. Txheeb xyuas cov duab kos lub sijhawm.
03
Cov ntawv thov cov neeg muag khoom yog sau los ntawm cov neeg xav muag koj cov khoom.
Lawv qhia lub rooj tsavxwm golden, cov qauv zoo meej, cov xwm txheej zoo tagnrho. Koj qhov mileage yuav txawv. Nyeem daim ntawv ceeb toom app rau cov ntsiab lus, tom qab ntawd txheeb xyuas nrog koj tus kheej ntsuas.
04
Yam kuv siv tiag tiag
Cov no tsis yog kev pom zoo-Kuv tsis muaj kev sib raug zoo nyiaj txiag nrog rau ib qho chaw tsim khoom-tsuas yog kev soj ntsuam los ntawm cov khoom xa tuaj.
RauDSAs qis dua 6 GHz: pSemi PE43711 (31.5 dB, 0.25 dB cov kauj ruam, glitch-resistant) lossis pheej yig dua PE4312 (31.5 dB, 0.5 dB cov kauj ruam). Ob leeg ua haujlwm. Ob leeg muaj quirks. Ob leeg muaj keeb kwm kev ua lag luam txaus uas qhov errata paub.
Raunruam attenuation (VVAs): Mini-Circuits ZX76 series thaum nyiaj tso cai. Skyworks SKY12347 thaum nws tsis. Tsis yog zoo tag nrho ntawm qhov kub thiab txias. Npaj raws li.
Rauhigh frequency (>20 GHz): Ua siab ncaj, kuv hu rau cov chaw tsim khoom thiab muaj kev sib tham. Analog Devices thiab Qorvo ob leeg muaj qhov chaw, kev xaiv tsis tshua muaj, thiab qhov kev xaiv "txoj cai" nyob ntawm koj qhov kev xav tau tshwj xeeb. Qhov no tsis yog khoom siv hluav taws xob- ntawm millimeter yoj, txhua yam yog kev cai.
Raukho qhov muag telecom: DiCon thiab Agiltron tau ntseeg tau. JDS Uniphase (tam sim no Viavi) ua cov khoom zoo tab sis cov khoom lag luam tau tawg los ntawm ntau qhov kev yuav khoom. Tshawb xyuas seb leej twg ua haujlwm tam sim no ua ntej koj cog lus.
Hom Failure Tsis muaj leej twg hais txog
ESD tua cov semiconductor attenuators. Qhov no tsis yog xov xwm. Dab tsi yog tham tsawg dua: qhov ua tsis tiav tuaj yeem hloov maj mam. Kuv tau pom qhov chaw uas tseem "ua haujlwm" tom qab ib qho kev tshwm sim ESD tab sis muaj degraded linearity los yog hloov attenuation calibration. Yog tias koj lub kaw lus dheev ua tsis tiav EMC kuaj rau lub hlis rau hauv kev tsim khoom, thiab koj tsis tau hloov dab tsi, mus xyuas lub attenuator. Tshwj xeeb tshaj yog tias koj lub tsev sib dhos hloov cov txheej txheem tuav.
PIN diodes ua tsis tau zoo - attenuation drifts, distortion nce -tab sis lawv tsis tshua tuag sai sai. FET keyboards hauv DSAs tsis nyuaj. Ib qho kev hloov luv luv, koj qhov attenuation tsis raug los ntawm 4 dB, thiab tshwj tsis yog tias koj tab tom saib xyuas qhov ntawd, lub kaw lus cia li ua tsis ncaj ncees lawm.
MEMS tsis ua haujlwm zoo li "pob" ua tsis tiav. Qhov hloov pauv tsis hloov. Nyob ntawm seb nws nyob qhov twg, koj tau txais ib qho channel tuag lossis ib qho chaw mus tas li - ntawm txoj kev. Cov cuab yeej ntsuas nrog MEMS attenuators yuav tsum tau ua haujlwm tsis tu ncua; keyboards uas zaum hauv ib txoj hauj lwm rau lub hlis tuaj yeem tsim "stiction."
Cas kuv tsis paub
Kuv tsis tau ua haujlwm nrogferrite-raws lihloov pauv attenuators. Txoj kev xav yog txias-magnetically-tuned absorption-tab sis qhov kuv tau pom yog qhov loj, lub zog- tshaib plab (cov electromagnet xav tau tam sim no), thiab txwv rau kev siv waveguide. Tej zaum yuav muaj cov ntawv thov uas lawv zoo tagnrho. Kuv tsis tau ntsib ib tus kheej.
Graphene-raws liattenuators muaj nyob rau hauv cov ntaub ntawv kawm. Supposedly lub tunability los ntawm qhov sib txawv ntawm Fermi theem thiab yog li cov conductivity. Kuv yuav ntseeg tias nws yog cov khoom tsim tawm -npaj thaum Digi- Cov khoom tseem ceeb nws.
Kuj tseem muaj haujlwmtheem- hloov cov ntaub ntawvrau RF hloov thiab attenuation. Lub tswv yim yog tias qee cov ntaub ntawv tuaj yeem hloov pauv ntawm amorphous thiab crystalline xeev siv thermal pulses, nrog rau cov khoom sib txawv ntawm RF hauv txhua lub xeev. Thaum ntxov.
Yog li ntawd yog cov toj roob hauv pes raws li kuv pom: PIN diodes rau analog tswj, DSAs rau digital precision, MEMS rau thaum koj xav tau qhov zoo tshaj plaws specs, mechanical for calibration and metrology, optical for fiber systems. Txhua tus muaj kev sib haum xeeb. Tsis yog universal. Cov engineers zoo tshaj plaws uas kuv paub xaiv cov thev naus laus zis raws li qhov lawv tuaj yeem zam tsis tau, tsis yog qhov ua haujlwm zoo tshaj plaws rau hnub ib.
Yog tias koj coj ib yam los ntawm qhov no: ntsuas qhov kub thiab txias. Kuaj ntawm cov ces kaum ntawm qhov attenuation ntau yam. Kuaj ntawm cov zaus uas koj xav tau tiag tiag, tsis yog qhov twg cov ntaub ntawv zoo li zoo nkauj tshaj plaws. Qhov uas ua haujlwm zoo kawg nkaus ntawm 25℃thiab 1 GHz yuav ntxeev siab rau koj ntawm -20℃thiab 5.8 GHz.
Nug kuv seb kuv paub li cas.
