Ob lub teeb liab thiab lub suab nrov hauv kev sib txuas lus tuaj yeem suav tias yog cov txheej txheem random uas sib txawv raws sijhawm.
Cov txheej txheem random muaj cov yam ntxwv ntawm qhov sib txawv ntawm qhov sib txawv thiab lub sijhawm ua haujlwm, thiab tuaj yeem piav qhia los ntawm ob qhov sib txawv tab sis zoo sib xws:①cov txheej txheem random yog ib phau ntawm cov qauv ua haujlwm tsis kawg;②Cov txheej txheem random yog ib txheej ntawm random variables.
Cov yam ntxwv ntawm cov txheej txheem random tau piav qhia los ntawm nws qhov kev faib ua haujlwm lossis qhov muaj peev xwm ceev ceev. Yog hais tias cov yam ntxwv ntawm cov txheej txheem random yog ywj siab ntawm lub sij hawm pib taw tes, nws yog hu ua tus txheej txheem nruj me ntsis.
Cov yam ntxwv digital yog lwm txoj hauv kev los piav qhia cov txheej txheem random. Yog hais tias tus nqi nruab nrab ntawm cov txheej txheem yog tas li thiab autocorrelation muaj nuj nqi R (T1, T1 + τ) = R (T), cov txheej txheem hu ua cov txheej txheem nyob ruaj ruaj.
Yog tias tus txheej txheem nruj nruj, nws yuav tsum ruaj khov; txwv tsis pub, tej zaum nws yuav tsis muaj tseeb.Yog hais tias lub sij hawm nruab nrab ntawm ib tug txheej txheem yog sib npaug zos rau cov txheeb cais nruab nrab, cov txheej txheem yog ergodic.Yog hais tias tus txheej txheem yog ergodic, nws tseem ruaj khov; txwv tsis pub, tej zaum nws yuav tsis muaj tseeb.
Lub autocorrelation muaj nuj nqi R (T) ntawm cov txheej txheem nyob ruaj ruaj yog ib qho tseem ceeb ntawm lub sij hawm sib txawv R, thiab R (0) yog sib npaug rau tag nrho lub zog nruab nrab, uas yog R (τ) tus nqi siab tshaj. Lub zog spectral ntom ntom (P) ξ (f) yog Fourier transform's autocorrelation muaj nuj nqi R () (Wiener Minchin theorem). Qhov khub ntawm kev hloov pauv no txiav txim siab hloov pauv kev sib raug zoo ntawm lub sijhawm thiab zaus zaus. Cov txheej txheem Gaussian qhov kev faib tawm qhov tshwm sim ua raws li qhov kev faib tawm ib txwm, thiab nws cov lus piav qhia ua tiav tsuas yog yuav tsum muaj nws tus lej xwb. Qhov ib-dimensional probability faib tsuas yog nyob ntawm qhov nruab nrab thiab variance, thiab ob-dimensional probability faib feem ntau yog nyob ntawm cov correlation muaj nuj nqi. Cov txheej txheem Gaussian tseem yog txheej txheem Gaussian tom qab kev hloov pauv. Kev sib raug zoo ntawm kev faib khoom ib txwm muaj thiab Q (x) lossis ERF (x) muaj nuj nqi yog qhov muaj txiaj ntsig zoo hauv kev tshuaj xyuas cov suab nrov ntawm kev sib txuas lus digital. Cov txheej txheem stochastic uas nyob ruaj ruaj Tom qab kuv (T) dhau los ntawm cov kab hluav taws xob, nws cov txheej txheem tso zis ξ 0 (T) kuj ruaj khov.
Cov yam ntxwv ntawm cov txheej txheem nqaim-band random thiab sine nthwv dej ntxiv rau qhov nqaim-band Gaussian suab nrov yog qhov tsim nyog rau kev tshuaj xyuas ntawm cov tshuab hloov kho, band-pass systems, thiab kev sib txuas lus wireless fading multipath channels. Peb qhov kev faib ua feem ntau hauv kev sib txuas lus yog Rayleigh kev faib khoom, kev faib mov, thiab kev faib tawm ib txwm: lub hnab ntawv ntawm lub teeb liab sinusoidal carrier thiab nqaim band. Gaussian suab nrov feem ntau yog kev faib mov. Thaum lub teeb liab amplitude loj, nws nyhav rau ib txwm faib; thaum lub amplitude me me, nws yog kwv yees li Rayleigh faib.
Gaussian dawb suab nrov yog tus qauv zoo tshaj plaws los soj ntsuam cov suab nrov ntxiv ntawm cov channel, thiab lub suab nrov tseem ceeb hauv kev sib txuas lus thermal suab nrov yog cov suab nrov no. Nws cov txiaj ntsig ntawm ob lub sijhawm sib txawv tsis sib xws thiab tsis muaj kev txheeb cais. Tom qab lub suab nrov dawb dhau los ntawm qhov band-limited system, qhov tshwm sim yog suab nrov band-limited. Tsawg pass dawb suab nrov thiab bandpass dawb suab nrov yog muaj nyob rau hauv theoretical tsom xam.
Cov lus saum toj no yog tsab xov xwm "random txheej txheem ntawm kev sib txuas lus" coj los rau koj los ntawm Shenzhen HDV phoelectron Technology Co., Ltd. vam tias tsab xov xwm no tuaj yeem pab koj kom koj paub ntau ntxiv. Dhau li ntawm tsab xov xwm no yog tias koj tab tom nrhiav rau lub tuam txhab kev sib txuas lus zoo fiber ntau cov khoom lag luam koj tuaj yeem xav txogtxog peb.
Shenzhen HDV phoelectron Technology Co., Ltd. yog ib qho chaw tsim khoom ntawm kev sib txuas lus. Tam sim no, cov cuab yeej tsim tawm npog covONU series, Optical module series, OLT series, thiabtransceiver series. Peb tuaj yeem muab cov kev pabcuam customized rau cov xwm txheej sib txawv. Zoo siab txais tossab laj.
