Tlhaloso e Felletseng ea Crystal Oscillator Random Jitter, Deterministic Jitter, le Phase Noise

Tlhaloso e Felletseng ea Crystal Oscillator Random Jitter, Deterministic Jitter, le Phase Noise

Crystal oscillator (XO/TCXO/OCXO) ke setsi sa tšebetso ea elektroniki, se fanang ka nako ea litšupiso bakeng sa li-CPU, li-FPGA, le-mahokelo a lebelo a holimo. Jitter ke metric ea mantlha ea ho lekola ho nepahala ha oache - e bua ka nako e khelohang lipakeng tsa lets'oao la oache le moeli o nepahetseng, oo hangata o utloisisoang e le "phoso ea nako" ea oache.

Jitter ea oscillator ea kristale ha e tsoe mohloling o le mong; e ka aroloa ka lihlopha tse peli tse kholo: Deterministic Jitter (DJ) le Random Jitter (RJ). Ho boenjineri, jitter e lekoa ho latela maemo a kang RMS Phase Jitter, RMS Period Jitter, le Cycle-ho{2}}Cycle (CC) Jitter. Litekanyetso tsena li hokahane empa li hlalosa litekanyo tse fapaneng tsa jitter.

1. Mefuta e Mebeli ea Motheo ea Jitter: Deterministic Jitter (DJ) vs. Random Jitter (RJ)

Ena ke karolo ea bohlokoa ka ho fetisisa ea kristale oscillator jitter. Tse peli li fapane ka ho feletseng ka tšimoloho, litšoaneleho le ho ntlafatsa.

1.1 Deterministic Jitter (DJ)

Jitter e tloaelehileng, e ka latelloang, le e moeling, e nkoang e le "phoso e ka lokisoang e bakoang ke tšitiso e ka ntle."

Mehloli: Ripple ea phepelo ea motlakase, PCB crosstalk, phallo e fapaneng ea mojaro, EMI, tšitiso ea potoloho ea mosebetsi, lerata le fetohang ka nako e le 'ngoe

Litšobotsi: E ka hlahisoa hape, e seng-kabo ea Gaussia, e lekanyelitsoe, e ka felisoa

Papiso: Oache e tsukutloang kamehla; phoso e ema ha ho tsitsinyeha ho emisa

1.2 Random Jitter (RJ)

Jitter e sa tloaelehang, e sa lebelloang, le e se nang moeli o ka holimo, e emelang "lerata la tlhaho" la kristale oscillator.

Mehloli: Lerata la mocheso, lerata le fokolang, ho feto-fetoha ha mochine, le lerata le leng la 'mele

Litšobotsi: Kabo ea Gaussian, e ke ke ea felisoa ka ho feletseng, e fokotseha feela

Papiso: Ho fetoha ho honyane ha tlhaho ka har'a oache ka boeona

1.3 Total Jitter (TJ)

Kakaretso ea jitter ke boemo bo holimo ba tse peli.Maemo a RMS a kopantsoe ke tlatsetso ea matla:TJRMS​{1}}RJRMS2​+DJRMS2​​

2. O tlameha-Ho Tseba Melao ea Boenjiniere: 4 Key Jitter Parameters

2.1 RMS Phase Jitter (Random)

E na le Random Jitter (RJ) feela

E emela karolo ea kahare ea lerata ea lerata la kristale oscillator

E bonahatsa boleng ba kristale ka boeona, ntle le tšitiso ea potoloho

2.2 RMS Phase Jitter (Kakaretso)

E kenyelletsa RJ + DJ

Karolo e sebelisoang haholo ea phase jitter metric e bonts'ang-lisebelisoa tsa 'nete tsa sistimi

2.3 RMS Period Jitter

Phapang ea RMS ea nako ea saekele e le 'ngoe ho tloha ho bolelele bo loketseng ba potoloho

E hlahisa{0}} botsitso ba nako e telele

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

Ho feto-fetoha ha phapano lipakeng tsa lipotoloho tse peli tse bapileng

E bonahatsa ho fetoha ha hang-hang; E bohlokoa haholo bakeng sa-mahokelo a lebelo a holimo

3. Kamano pakeng tsa Parameters le DJ / RJ

Kakaretso ea Bohlokoa:

Feela Random Phase Jitter=pure RJ

Tse ling kaofela=RJ + deterministic interference (DJ)

4. Kopo ea Boenjiniere: Mokhoa oa ho Toloka le ho Rarolla Mathata

Lekola boleng ba kristale oscillator → hlahloba RMS Phase Jitter (E sa tloaelehang)

Lekola-ts'ebetso ea sistimi → lekola RMS Phase Jitter (Kakaretso)

Likhokahano tse phahameng-tse lebelo (PCIe/USB) → tsepamisa maikutlo ho CC Jitter

Haeba jitter e le ngata, hlahloba pele: matla, fatše, crosstalk, mojaro (mehloli eohle ea DJ)

5. Kamano Pakeng tsa Jitter le Phase Noise (Time Domain ↔ Frequency Domain)

5.1 Moelelo oa Motheo Polelong e le 'Ngoe

Phase Noise=frequency{1}}sesupo sa domain

Phase Jitter=nako{1}}sesupo sa sebaka

Ke mahlakore a mabeli a chelete ea tšepe e le 'ngoe' me a ka fetoloa ho e mong.

5.2 Lingollano tsa Sehlooho

RMS Random Phase Jitter↔ e baloa ka kotloloho ka ho kopanya lerata la karolo holim'a bandwidth e hlalositsoeng

Deterministic Jitter (DJ)↔ e lumellana le li-spurs tsa discrete sebakeng sa lerata la lerata

Random Jitter (RJ)↔ e lumellana le lerata le tsoelang pele la lerata la mohato

5.3 Phetoho ea Boenjiniere

Ho kopanya lerata la mohato L(f) holim'a frequency offset range ka kotloloho ho hlahisa RMS Phase Jitter.

Kutloisiso e nolofalitsoeng:

Boemo ba sekhahla sa lerata → bo lekanya boholo ba jitter

Mokokotlo o tlase le o bataletseng → jitter e nyane

Li-spikes (spurs) lia hlaha → Deterministic Jitter (DJ)

5.4 'Mapa o Intuitive

Mohato oa lerata → Random Jitter (RJ) (e ke ke ea tlosoa)

Phase lerata la spurs → Deterministic Jitter (DJ) (e ka rarolloa)

Ho kopanya molumo o felletseng oa lerata → kakaretso ea RMS Phase Jitter

6. Final Ultra-Kakaretso e Khutšoanyane

Jitter e na le mekhahlelo e 'meli:

DJ (Deterministic Jitter): tšitiso ea ka ntle, e ka felisoa

RJ (Random Jitter): lerata la tlhaho la kristale,{0}}o ke keng oa felisoa

Liparamente tse tloaelehileng:

RMS Random Phase Jitter=e hloekileng ea RJ

RMS Total Phase Jitter=RJ + DJ

Period Jitter=single{1}}cycle stability

CC Jitter=e bapileng-ho fapana ha potoloho

Jitter ↔ Phase Lerata:

Phase Noise (domain frequency) ↔ Phase Jitter (sebaka sa nako)

Mokatong o lerata → RJ

Spurs → DJ

Mokhahlelo oa ho kopanya lerata → o hlahisa RMS Phase Jitter ka kotloloho