Ntawm no, plaub yam tseem ceeb ntawm xov tooj cua zaus circuits yuav raug txhais los ntawm plaub yam: xov tooj cua zaus interface, me me xav tau teeb liab, teeb liab cuam tshuam loj, thiab cov kev cuam tshuam channel nyob ib sab, thiab cov yam tseem ceeb uas xav tau kev saib xyuas tshwj xeeb hauv PCB tsim txheej txheem tau muab.

Xov tooj cua zaus interface ntawm xov tooj cua zaus Circuit Court simulation

Lub wireless transmitter thiab receiver yog conceptually muab faib ua ob ntu: puag zaus thiab xov tooj cua zaus. Qhov tseem ceeb zaus suav nrog qhov ntau zaus ntawm cov teeb liab tawm tswv yim ntawm lub transmitter thiab qhov ntau zaus ntawm cov teeb liab tso tawm ntawm lub receiver. Lub bandwidth ntawm qhov tseem ceeb zaus txiav txim siab qhov tseem ceeb ntawm cov ntaub ntawv tuaj yeem ntws hauv qhov system. Lub hauv paus zaus yog siv los txhim kho kev ntseeg siab ntawm cov ntaub ntawv kwj thiab txo cov load imposed los ntawm lub transmitter ntawm kis nruab nrab nyob rau hauv ib tug tshwj xeeb cov ntaub ntawv kis tus nqi. Yog li ntawd, ntau lub teeb liab kev paub txog engineering yog xav tau thaum tsim ib qho tseem ceeb zaus Circuit Court ntawm PCB. Lub xov tooj cua zaus Circuit Court ntawm lub transmitter tuaj yeem hloov pauv thiab nce-hloov cov teeb liab ua tiav rau hauv ib qho channel, thiab txhaj cov teeb liab no rau hauv nruab nrab kis. Ntawm qhov tsis sib xws, lub xov tooj cua zaus Circuit Court ntawm lub receiver tuaj yeem tau txais cov teeb liab los ntawm qhov nruab nrab ntawm kev sib kis, thiab hloov thiab txo qhov zaus mus rau lub hauv paus zaus.
Transmitter muaj ob lub hom phiaj tseem ceeb ntawm PCB tsim: Thawj yog tias lawv yuav tsum xa ib lub zog tshwj xeeb thaum siv lub zog tsawg kawg nkaus. Qhov thib ob yog tias lawv tsis tuaj yeem cuam tshuam nrog kev ua haujlwm ib txwm ntawm transceivers hauv cov kab uas nyob ib sab. Raws li tus neeg txais kev txhawj xeeb, muaj peb lub hom phiaj tseem ceeb ntawm PCB tsim: ua ntej, lawv yuav tsum tau kho cov teeb liab me me kom raug; thib ob, lawv yuav tsum muaj peev xwm tshem tawm cov teeb meem cuam tshuam sab nraud ntawm qhov xav tau channel; thiab qhov kawg, zoo li lub transmitter, lawv yuav tsum haus lub zog me me heev.

Loj cuam tshuam teeb liab ntawm xov tooj cua zaus Circuit Court simulation

Lub receiver yuav tsum tau rhiab heev rau cov teeb liab me me, txawm tias thaum muaj teeb meem loj cuam tshuam (kev cuam tshuam). Qhov xwm txheej no tshwm sim thaum sim kom tau txais lub teeb liab tsis muaj zog lossis kev sib kis mus ntev, thiab lub zog xa hluav taws xob nyob ze tau tshaj tawm hauv cov channel uas nyob ib sab. Lub teeb liab cuam tshuam tuaj yeem yog 60 txog 70 dB loj dua li qhov xav tau teeb liab, thiab nws tuaj yeem raug them ntau thaum lub sij hawm nkag ntawm lub receiver, los yog lub receiver tuaj yeem tsim suab nrov heev thaum lub sij hawm nkag los thaiv kev txais tos ntawm ib txwm teeb liab. . Yog tias tus txais tau tsav mus rau hauv cheeb tsam uas tsis yog-linear los ntawm qhov cuam tshuam thaum lub sij hawm nkag mus, ob qho teeb meem saum toj no yuav tshwm sim. Txhawm rau zam cov teeb meem no, qhov kawg ntawm lub receiver yuav tsum yog linear heev.
Yog li, "linearity" kuj yog ib qho tseem ceeb rau kev txiav txim siab hauv PCB tsim ntawm tus txais. Txij li thaum lub receiver yog ib lub voj voog nqaim, qhov nonlinearity yog ntsuas los ntawm kev ntsuas "intermodulation distortion". Qhov no suav nrog kev siv ob lub sine nthwv dej lossis cosine nthwv dej nrog cov zaus zoo sib xws thiab nyob rau hauv qhov chaw nruab nrab kom tsav cov teeb liab tawm tswv yim, thiab tom qab ntawd ntsuas cov khoom ntawm nws cov intermodulation. Feem ntau hais lus, SPICE yog lub sijhawm siv sijhawm thiab siv nyiaj siv nyiaj ntau heev, vim tias nws yuav tsum tau ua ntau lub voj voog suav kom tau txais qhov kev daws teeb meem uas yuav tsum tau ua kom nkag siab txog qhov sib txawv.

Me me teeb liab nyob rau hauv RF Circuit Court simulation

Lub receiver yuav tsum tau rhiab heev los mus ntes me me input signals. Feem ntau hais lus, lub zog nkag ntawm lub receiver tuaj yeem ua me me li 1 μV. Lub rhiab heev ntawm lub receiver yog txwv los ntawm lub suab nrov generated los ntawm nws input circuit. Yog li, lub suab nrov yog qhov tseem ceeb hauv kev tsim PCB ntawm tus txais. Tsis tas li ntawd, lub peev xwm los kwv yees suab nrov nrog cov cuab yeej simulation yog qhov tseem ceeb. Daim duab 1 yog ib qho superheterodyne receiver. Lub teeb liab tau txais yog lim ua ntej, thiab tom qab ntawd cov teeb liab tawm tswv yim yog amplified los ntawm lub suab nrov nrov amplifier (LNA). Tom qab ntawd siv thawj lub zos oscillator (LO) sib tov nrog cov teeb liab no los hloov cov teeb liab no mus rau qhov nruab nrab zaus (IF). Lub suab nrov ntawm lub hauv ntej-kawg Circuit Court feem ntau yog nyob ntawm LNA, tov khoom thiab LO. Txawm hais tias qhov kev tshuaj ntsuam SPICE ib txwm muaj peev xwm nrhiav tau lub suab nrov ntawm LNA, nws tsis muaj txiaj ntsig rau cov khoom sib tov thiab LO, vim tias cov suab nrov hauv cov blocks no yuav raug cuam tshuam loj heev los ntawm lub teeb liab LO loj.
Lub teeb liab me me yuav tsum tau txais lub receiver kom muaj lub zog loj, thiab feem ntau yuav tsum tau nce ntawm 120 dB. Nrog rau qhov kev nce siab zoo li no, txhua lub teeb liab sib txuas los ntawm qhov tso zis kawg rov qab mus rau qhov kev tawm tswv yim kawg yuav ua rau muaj teeb meem. Qhov laj thawj tseem ceeb ntawm kev siv superheterodyne receiver architecture yog tias nws tuaj yeem faib qhov nce hauv ntau zaus kom txo tau txoj hauv kev sib txuas. Qhov no kuj ua rau qhov zaus ntawm thawj LO txawv ntawm qhov zaus ntawm lub teeb liab tawm tswv yim, uas tuaj yeem tiv thaiv cov teeb liab cuam tshuam loj los ntawm kev "pab" rau cov teeb liab me me.
Rau cov laj thawj sib txawv, hauv qee qhov kev sib txuas lus wireless, kev hloov pauv ncaj qha lossis homodyne architecture tuaj yeem hloov superheterodyne architecture. Nyob rau hauv no architecture, RF input teeb liab yog ncaj qha hloov mus rau lub hauv paus zaus nyob rau hauv ib kauj ruam. Yog li ntawd, feem ntau ntawm qhov nce yog nyob rau hauv lub hauv paus zaus, thiab qhov zaus ntawm LO thiab lub teeb liab input yog tib yam. Hauv qhov no, qhov cuam tshuam ntawm qhov sib txuas me me yuav tsum tau nkag siab, thiab cov qauv ntxaws ntawm "txoj kev teeb liab" yuav tsum raug tsim, xws li: kev sib txuas los ntawm cov substrate, pob pins, thiab cov hlua khi (Bondwire) ntawm cov coupling, thiab coupling los ntawm lub hwj chim kab.

Kev cuam tshuam channel nyob ib sab hauv xov tooj cua zaus Circuit Court simulation

Distortion kuj plays lub luag haujlwm tseem ceeb hauv lub transmitter. Lub non-linearity generated los ntawm lub transmitter nyob rau hauv cov zis Circuit Court tej zaum yuav kis tau tus bandwidth ntawm lub transmission signals nyob rau hauv cov kab uas nyob ib sab. Qhov tshwm sim no hu ua "spectral regrowth". Ua ntej lub teeb liab mus txog lub transmitter lub hwj chim amplifier (PA), nws bandwidth yog txwv; tab sis qhov "intermodulation distortion" hauv PA yuav ua rau bandwidth nce ntxiv. Yog tias qhov bandwidth nce ntau dhau lawm, lub transmitter yuav tsis muaj peev xwm ua tau raws li qhov xav tau ntawm lub zog ntawm nws cov channel uas nyob ib sab. Thaum xa cov cim digitally modulated, qhov tseeb, SPICE tsis tuaj yeem siv los kwv yees qhov kev loj hlob ntxiv ntawm spectrum. Vim hais tias kev sib kis ntawm kwv yees li 1,000 lub cim (cim) yuav tsum tau simulated kom tau txais tus neeg sawv cev spectrum, thiab cov neeg siv hluav taws xob ntau zaus yuav tsum tau ua ke, uas yuav ua rau SPICE kev soj ntsuam tsis zoo.