Nkọwa zuru ezu nke Crystal Oscillator Random Jitter, Deterministic Jitter, na Phase Noise

Nkọwa zuru ezu nke Crystal Oscillator Random Jitter, Deterministic Jitter, na Phase Noise

Oscillator kristal (XO/TCXO/OCXO) bụ obi elekere nke sistemu eletrọnịkị, na-enye oge ntụaka maka CPUs, FPGAs, na ihu ọsọ ọsọ{{0} dị elu. Jitter bụ metric isi maka ịlele nzizi elekere - ọ na-ezo aka n'iche oge n'etiti nsọtụ nke mgbama elekere na ezigbo ihu, nke a na-aghọtakarị dị ka "njehie oge" nke elekere.

Jitter nke oscillator kristal adịghị esi n'otu ebe pụta; Enwere ike kewaa ya ụzọ abụọ bụ isi: Deterministic Jitter (DJ) na Random Jitter (RJ). Na injinia, a na-agbakọ jitter site na paramita dị ka RMS Phase Jitter, RMS Period Jitter, na Cycle-na{{2}Cycle (CC) Jitter. Paragraf ndị a nwere njikọ chiri anya mana na-akọwa akụkụ dị iche iche nke jitter.

1. Ụdị abụọ dị mkpa nke Jitter: Deterministic Jitter (DJ) vs. Random Jitter (RJ)

Nke a bụ ọkwa kachasị mkpa nke kristal oscillator jitter. Ha abụọ dị iche kpamkpam na mmalite, njirimara, na njikarịcha.

1.1 Deterministic Jitter (DJ)

Jitter bụ nke a na-ahụkarị, nke a na-achọpụta, na nke nwere oke, nke a na-ewere dị ka "njehie nwere ike imezi site na nnyonye anya mpụga."

Isi mmalite: ọkụ ọkọnọ ripple, PCB crosstalk, ibu adabaghị, EMI, mgbagha okirikiri ọrụ, mkpọtụ mgbanwe n'out oge.

Àgwà: enwere ike imepụtagharị, enweghị-nkesa Gaussian, kpara ókè, enweghị ike iwepụ.

Analogy: A na-amagharị elekere mgbe niile; njehie ahụ na-akwụsị mgbe ịma jijiji ahụ kwụsịrị

1.2 Random Jitter (RJ)

Jitter nke na-adịghị agbanwe agbanwe, nke a na-atụghị anya ya, na enweghị oke elu zuru oke, na-anọchite anya "mkpọtụ ebumpụta ụwa" nke oscillator kristal.

Isi mmalite: mkpọtụ okpomọkụ, mkpọtụ na-egbuke egbuke, mgbanwe ụgbọ mmiri, na mkpọtụ anụ ahụ ndị ọzọ

Njirimara: nkesa Gaussian, enweghị ike ikpochapụ kpamkpam, naanị belata

Analogy: Obere mgbanwe okike n'ime elekere n'onwe ya

1.3 ngụkọta Jitter (TJ)

Ezigbo mkpokọta jitter bụ ihe kachasị elu nke abụọ ahụ. A na-ejikọta ụkpụrụ RMS site na mgbakwunye ike:TJRMS=RJRMS2+DJRMS2

2. Ga-enwerịrị-mara Usoro injinia: 4 igodo Jitter Parameters

2.1 RMS Usoro Jitter (enweghị usoro)

Nwere naanị Random Jitter (RJ)

Na-anọchite anya ụda mkpọtụ nke akụkụ dị mkpa nke oscillator kristal

Na-egosipụta àgwà kristal n'onwe ya, na-adabereghị na nnyonye anya sekit

2.2 RMS Usoro Jitter (Mkpokọta)

Ọ gụnyere RJ + DJ

Usoro jitter metric nke a na-ejikarị eme ihe nke na-egosipụta ezigbo arụmọrụ sistemu{{0}

2.3 RMS Oge Jitter

Mgbanwe RMS nke ogologo oge okirikiri site na ogologo okirikiri dị mma

Na-egosipụta nkwụsi ike okirikiri ogologo oge{{0}

2.4 okirikiri - ka -Cycle Jitter (CC Jitter)

Mgbanwe na ọdịiche dị n'etiti okirikiri abụọ dị n'akụkụ

Na-egosipụta mgbanwe ozugbo; dị oke egwu maka oke ọsọ ọsọ{{0}

3. Mmekọrịta n'etiti Parameters na DJ / RJ

Nchịkọta igodo:

Naanị Random Phase Jitter=RJ dị ọcha

Ndị ọzọ niile=RJ + nnyonye anya deterministic (DJ)

4. Ngwa Injinia: Otu esi atụgharị na nchọpụta nsogbu

Nyochaa ogo oscillator kristal → lelee RMS Phase Jitter (Random)

Nyochaa ezigbo arụmọrụ sistemu{{0} → lelee RMS Phase Jitter (Mkpokọta)

Ọsọ ọsọ{{0} dị elu (PCIe/USB) → gbadoro anya na CC Jitter

Ọ bụrụ na jitter karịrị akarị, lelee mbụ: ike, ala, crosstalk, ibu (isi iyi DJ niile)

5. Mmekọrịta n'etiti Jitter na Usoro mkpọtụ (Ngalaba Oge ↔ ngalaba ugboro)

5.1 Isi echiche n'otu ahịrịokwu

Usoro mkpọtụ=ugboro - akara ngalaba

Usoro Jitter=oge - ihe ngosi ngalaba

Ha bụ akụkụ abụọ nke otu mkpụrụ ego ma nwee ike ịtụgharị n'ime ibe ha.

5.2 Mkparịta ụka igodo

RMS Random Phase Jitter↔ gbakọọ ozugbo site na ijikọ mkpọtụ usoro n'elu bandwit akọwapụtara

Deterministic Jitter (DJ) ↔ kwekọrọ na mkpali pụrụ iche na nkata mkpọtụ nke akụkụ

Random Jitter (RJ) ↔ kwekọrọ n'ala mkpọtụ na-aga n'ihu nke mkpọtụ oge

5.3 Ntụgharị Injinia

Ịgbakwunye ụda olu L(f) n'usoro ngbanwe ugboro ugboro na-enye RMS Phase Jitter ozugbo.

Nghọta dị mfe:

Ọkwa nke usoro mkpọtụ mkpọtụ → na-ekpebi oke jitter

Ọkpụkpụ ala & nke na-atọ ụtọ → obere jitter

Spikes (spurs) pụtara → Deterministic Jitter (DJ)

5.4 Nkewa ihe omimi

Ala mkpọtụ mkpọtụ → Random Jitter (RJ) (enweghị ike iwepụ)

mkpọtụ mkpọtụ na-akpali → Deterministic Jitter (DJ) (enwere ike idozi nsogbu)

Na-ejikọta ụdị ụda mkpọtụ zuru ezu → mkpokọta RMS Phase Jitter

6. Final Ultra{1}Nchịkọta nkenke

Jitter nwere ụdị abụọ:

DJ (Deterministic Jitter): nnyonye anya mpụga, enwere ike iwepụ

RJ (Random Jitter): mkpọtụ kristal pụtara, enweghị ike iwepụ

Ihe ndị a na-ahụkarị:

RMS Random Phase Jitter=RJ dị ọcha

RMS ngụkọta oge Jitter=RJ + DJ

Oge Jitter=otu - nkwụsi ike okirikiri

CC Jitter=n'akụkụ{1} mgbanwe okirikiri

Jitter ↔ Usoro mkpọtụ:

Usoro Noise (ngalaba ugboro) ↔ Oge Jitter (ngalaba oge)

Ala mkpọtụ → RJ

Spurs → DJ

Njikọ mkpọtụ usoro → na-ewepụta RMS Phase Jitter ozugbo