Inkcazo eneenkcukacha yeCrystal Oscillator Random Jitter, Deterministic Jitter, kunye neNgxolo yeSigaba

Inkcazo eneenkcukacha yeCrystal Oscillator Random Jitter, Deterministic Jitter, kunye neNgxolo yeSigaba

I-crystal oscillator (XO/TCXO/OCXO) yintliziyo yewotshi yeenkqubo zombane, ibonelela ngereferensi yexesha le-CPUs, iiFPGA, kunye -nonxibelelwano olukhawulezayo. IJitter yimetric engundoqo yokuvavanya ukuchaneka kwewotshi - ibhekisa ekuphambukeni kwexesha phakathi kowona mngcelele wesiginali yewotshi kunye nesiphelo esifanelekileyo, esiqhele ukuqondwa njenge "impazamo yexesha" yewotshi.

I-jitter ye-crystal oscillator ayiveli kumthombo omnye; inokwahlulwa ibe ngamacandelo amabini amakhulu: iDeterministic Jitter (DJ) kunye neRandom Jitter (RJ). Kubunjineli, ijita ibalwa ngokweeparamitha ezifana neRMS Phase Jitter, RMS Period Jitter, kunye neCycle-ukuya{2}}Cycle (CC) Jitter. Ezi parameters zinxulumene kodwa zichaza imilinganiselo eyahlukeneyo yejitter.

1. Iindidi ezimbini eziSisiseko zeJitter: IJitter yeDeterministic (DJ) vs. Random Jitter (RJ)

Olu lolona luhlelo lubalulekileyo lwejita ye-crystal oscillator. Ezi zimbini zahluke ngokupheleleyo ngemvelaphi, iimpawu, kunye nokwenziwa ngcono.

1.1 IJitter eqinisekileyo (DJ)

IJitter eqhelekileyo, iyalandeleka, kwaye ibotshelelwe, ithathwa ngokuba "yimpazamo enokulungiswa ebangelwa kukuphazamiseka kwangaphandle."

Imithombo: Umbane wombane, i-PCB crosstalk, ukungahambi kakuhle komthwalo, i-EMI, ukuphazamiseka komjikelo womsebenzi, ingxolo yokutshintsha ngaxeshanye

Iimpawu: Iyaphindaphindeka, ayiyo{0}}Usasazo lweGaussian, iyabotshwa, iyacinywa

Isifaniso: Iwotshi eshukunyiswa rhoqo; impazamo iyayeka xa ukungcangcazela kuyeka

1.2 Random Jitter (RJ)

IJitter engaqhelekanga, engalindelekanga, kwaye ngaphandle komda ongaphezulu, omele "ingxolo yendalo yendalo" ye-crystal oscillator.

Imithombo: Ingxolo yobushushu, ingxolo ephaphazelayo, ukuguquguquka komthwali, kunye nezinye ingxolo yomzimba

Iimpawu: Ukusabalalisa kwe-Gaussian, ayikwazi ukupheliswa ngokupheleleyo, kuncitshiswe kuphela

Isifaniso: Ukuguquguquka okuncinci kwendalo ngaphakathi kwewotshi ngokwayo

1.3 Iyonke iJitter (TJ)

Eyona jita iyonke yi-superposition yezi zimbini. Amaxabiso e-RMS adityaniswa ngokongezwa kwamandla:TJRMS​{1}}RJRMS2​+DJRMS2​​

2. Kufuneka{1}}Yazi iMigaqo yobuNjineli: 4 iiParamitha zeJitter ezingundoqo

2.1 RMS Phase Jitter (Random)

Iqulathe kuphela iJitter eRandom (RJ)

Imele umgangatho wengxolo wesigaba sangaphakathi se-crystal oscillator

Ibonakalisa umgangatho wekristale ngokwayo, ezimeleyo ekuphazamisekeni kwesekethe

2.2 I-RMS yeSigaba seJitter (Itotali)

Kubandakanya iRJ + DJ

Esona sigaba sixhaphakileyo se-jitter metric ebonisa{0}}inkqubo yokusebenza yokwenyani

2.3 IJitter yeXesha le-RMS

Ukutenxa kwe-RMS yobude bexesha lomjikelo omnye ukusuka kubude obufanelekileyo bomjikelo

Ibonakalisa{0}} uzinzo lomjikelo wexesha elide

2.4 Cycle -ukuya{2}}Cycle Jitter (CC Jitter)

Ukuguquguquka kumahluko phakathi kwemijikelo emibini emeleneyo

Ibonakalisa ukuguquguquka kwangoko; ibaluleke kakhulu-kunxibelelwano olukhawulezayo

3. Ubudlelwane phakathi kweeParameters kunye ne-DJ / RJ

Isishwankathelo esingundoqo:

Kuphela i-Random Phase Jitter=i-RJ esulungekileyo

Bonke abanye=RJ + uphazamiseko olumiselayo (DJ)

4. ISicelo sobuNjineli: Indlela yokuTolika kunye nokuQothulwa kweNgxaki

Vavanya umgangatho we-crystal oscillator → khangela i-RMS yeSigaba seJitter (Ngokungaqhelekanga)

Vavanya eyona -ukusebenza kwenkqubo → khangela i-RMS yeSigaba seJitter (Itotali)

Ujongano oluphezulu- lwesantya (PCIe/USB) → qwalasela kwi-CC Jitter

Ukuba i-jitter igqithise, jonga kuqala: amandla, umhlaba, i-crosstalk, umthwalo (yonke imithombo ye-DJ)

5. Ubudlelwane phakathi kweJitter kunye neNgxolo yeSigaba (I-Domain yeXesha ↔ I-Frequency Domain)

5.1 Ingcinga engundoqo kwisivakalisi esinye

Ingxolo yeSigaba=rhoqo-isalathisi sendawo

Isigaba seJitter=ixesha{1}}isalathisi sommandla

Zingamacala amabini engqekembe enye kwaye zinokuguqulwa zibe enye kwenye.

5.2 Imbalelwano engundoqo

I-RMS Random Phase Jitter↔ ibalwe ngokuthe ngqo ngokuhlanganisa ingxolo yesigaba ngaphaya komda ochaziweyo

I-Deterministic Jitter (DJ)↔ ihambelana ne-discrete spurs kwisakhiwo sengxolo yesigaba

Random Jitter (RJ)↔ ihambelana nomgangatho wengxolo oqhubekayo wengxolo yesigaba

5.3 Uguqulo lobuNjineli

Ukudibanisa inqanaba lengxolo L(f) phezu koluhlu oluphindaphindayo luvelisa ngokuthe ngqo i-RMS Phase Jitter.

Ukuqonda lula:

Inqanaba legophe lengxolo yesigaba → limisela ubungakanani bejita

Igophe elisezantsi & elicaba → ijitha elincinci

Izipika (spurs) zivela → Deterministic Jitter (DJ)

5.4 Imephu eqondakalayo

Inqanaba lomgangatho wengxolo → IJitter eNgameleyo (RJ) (ayinakususwa)

Inqanaba lengxolo yenqanaba → Deterministic Jitter (DJ) (inokulungiswa)

Ukudibanisa i-spectrum yengxolo epheleleyo → iyonke i-RMS yeSigaba seJitter

6. Okokugqibela-Isishwankathelo esifutshane

IJitter ineendidi ezimbini:

DJ (Deterministic Jitter): ukuphazamiseka kwangaphandle, ukuphelisa

RJ (Random Jitter): ingxolo eyikristale engokwemvelo,-engenakucinywa

Iiparamitha eziqhelekileyo:

I-RMS yeSigaba esiHlangeneyo iJitter=i-RJ esulungekileyo

I-RMS yeSigaba Sisonke iJitter=RJ + DJ

Ixesha leJitter=olulodwa{1}}lozinzo lomjikelo

I-CC Jitter=ecaleni{1}}umahluko womjikelo

Jitter ↔ Ingxolo yeSigaba:

Ingxolo yeSigaba (i-domain ye-frequency) ↔ i-Phase Jitter (i-time domain)

Umgangatho wengxolo → RJ

Spurs → DJ

Inqanaba lokudityaniswa kwengxolo → ivelisa ngokuthe ngqo i-RMS Phase Jitter