Cikakken Bayani na Crystal Oscillator Random Jitter, Deterministic Jitter, and Phase Noise

Cikakken Bayani na Crystal Oscillator Random Jitter, Deterministic Jitter, and Phase Noise

A crystal oscillator (XO/TCXO/OCXO) shine agogon zuciyar tsarin lantarki, yana ba da lokacin tunani don CPUs, FPGAs, da manyan musaya masu sauri{0}. Jitter shine ainihin ma'auni don kimanta daidaitaccen agogo - yana nufin karkatar da lokaci tsakanin ainihin gefen siginar agogo da madaidaicin gefen, wanda aka fi sani da "kuskuren lokaci" na agogo.

Jitter na oscillator crystal baya fitowa daga tushe guda; Ana iya raba shi zuwa manyan nau'i biyu: Deterministic Jitter (DJ) da Random Jitter (RJ). A aikin injiniya, ana ƙididdige jitter ta sigogi kamar RMS Phase Jitter, RMS Period Jitter, da Cycle{1} zuwa{2}Cycle (CC) Jitter. Waɗannan sigogi suna da alaƙa amma suna bayyana nau'ikan jitter daban-daban.

1. Nau'ukan Jitter Biyu: Ƙididdigar Jitter (DJ) vs. Random Jitter (RJ)

Wannan shine mafi mahimmancin rabe-raben kristal oscillator jitter. Biyu sun bambanta gaba ɗaya a asali, halaye, da ingantawa.

1.1 Ƙaddamarwa Jitter (DJ)

Jitter wanda yake na yau da kullun, wanda ake iya ganowa, kuma yana da iyaka, ana ɗaukarsa azaman "kuskuren gyara wanda ya haifar da tsangwama na waje."

Madogarawa: Ripple na samar da wutar lantarki, PCB crosstalk, rashin daidaiton kaya, EMI, murdiya sake zagayowar aiki, hayaniyar sauya lokaci guda

Halaye: Ba za a iya sakewa ba, ba -Rarraba Gaussian, iyaka, da za a iya cirewa

Misali: Ana girgiza agogo akai-akai; kuskuren yana tsayawa lokacin girgizar ta tsaya

1.2 Random Jitter (RJ)

Jitter wanda ba bisa ka'ida ba, maras tabbas, kuma ba tare da cikakkiyar iyaka ta sama ba, yana wakiltar "hayaniyar hayaniyar halitta" na oscillator crystal.

Maɓuɓɓuka: Hayaniyar zafi, amo mai ƙyalli, jujjuyawar jigilar kaya, da sauran surutu na zahiri

Halaye: rarraba Gaussian, ba za a iya kawar da shi gaba daya ba, kawai ragewa

Analogy: Ƙananan jujjuyawar yanayi a cikin agogon kanta

1.3 Jimlar Jitter (TJ)

Ainihin jimlar jitter shine babban matsayi na biyu. Ana haɗe kimar RMS ta hanyar ƙara ƙarfi:TJRMS=RJRMS2+DJRMS2​​

2. Dole ne -Sanin Sharuɗɗan Injiniya: 4 Maɓalli na Jitter

2.1 RMS Phase Jitter (Bazuwar)

Ya ƙunshi Random Jitter (RJ) kawai

Yana wakiltar ainihin hayaniyar bene na oscillator crystal

Yana nuna ingancin kristal da kansa, mai zaman kansa ba tare da tsangwama ba

2.2 RMS Phase Jitter (Jimlar)

Ya hada da RJ + DJ

Mafi yawan amfani da awo na jitter wanda ke nuna ainihin aikin tsarin{{0}

2.3 RMS Lokacin Jitter

RMS na tsawon lokacin zagayowar guda ɗaya daga madaidaicin tsayin zagayowar

Yana Nuna kwanciyar hankali na tsawon lokaci{0}

2.4 Zagayowar -zuwa{2}}Cycle Jitter (CC Jitter)

Canje-canje a cikin bambanci tsakanin hawan keke biyu maƙwabta

Yana nuna bambancin nan take; mai matuƙar mahimmanci ga manyan musaya masu saurin gudu{0}

3. Dangantaka Tsakanin Ma'auni da DJ/RJ

Mabuɗin Takaitaccen Bayani:

Jitter Bazuwar Lokaci kawai=tsantsar RJ

Duk wasu=RJ + tsangwama mai iyaka (DJ)

4. Aikace-aikacen Injiniya: Yadda ake Fassara da Matsala

Ƙimar ingancin oscillator crystal → duba RMS Phase Jitter (Random)

Ƙimar aiki na gaske- → duba RMS Phase Jitter (Total)

Babban -Masu musanyar saurin gudu (PCIe/USB) → mai da hankali kan CC Jitter

Idan jitter ya wuce kima, dubawa na farko: iko, ƙasa, crosstalk, lodi (duk tushen DJ)

5. Dangantaka Tsakanin Jitter da Hayaniyar Lokaci (Lokaci Domain ↔ Domain Frequency)

5.1 Mahimman ra'ayi a cikin Jumla ɗaya

Hayaniyar lokaci=mitar -mai nuna yanki

Matakin Jitter=lokaci{1}}mai nuna yanki

Bangaren tsabar kuɗi ɗaya ne kuma ana iya jujjuya su zuwa juna.

5.2 Maɓalli Maɓalli

RMS Random Phase Jitter↔ kai tsaye ana ƙididdige su ta hanyar haɗa hayaniyar lokaci akan ƙayyadadden bandwidth

Deterministic Jitter (DJ) ↔ yayi daidai da ƙwaƙƙwaran ƙira a cikin shirin amo na zamani

Random Jitter (RJ) ↔ yayi daidai da ci gaba da amo bene na amo

5.3 Canjin Injiniya

Haɗa hayaniyar lokaci L(f) akan kewayon mitar biya kai tsaye yana haifar da RMS Phase Jitter.

Fahimtar Sauƙaƙe:

Matsayin yanayin amo na lokaci → yana ƙayyade girman jitter

Ƙananan & lanƙwasa → ƙarami jitter

Spikes (spurs) suna bayyana → Deterministic Jitter (DJ)

5.4 Taswirar Ilhama

Hayaniyar yanayi → Random Jitter (RJ) (ba za a iya cirewa ba)

Hayaniyar lokaci → Deterministic Jitter (DJ) (ana iya magance matsalar)

Haɗa cikakken bakan amo → jimlar RMS Phase Jitter

6. Final Ultra{1}Takaitaccen Takaitaccen Takaitaccen Takaitaccen Tarihin

Jitter yana da nau'i biyu:

DJ (Deterministic Jitter): tsangwama na waje, wanda za a iya kawar da shi

RJ (Random Jitter): amo na asali, wanda ba za a iya kawar da shi ba

Alamomin gama gari:

RMS Random Phase Jitter=tsaftataccen RJ

Jitter Jumla na RMS {0} RJ + DJ

Zaman Jitter=guda - kwanciyar hankali

CC Jitter=bambancin zagayowar -

Jitter ↔ Hayaniyar Mataki:

Hayaniyar lokaci (yankin mitar) ↔ Mataki na Jitter (yankin lokaci)

Hayaniya → RJ

Spurs → DJ

Haɗin amo na lokaci → kai tsaye yana haifar da RMS Phase Jitter