Hobaneng ha Lisebelisoa tsa Marang-rang li Sebelisa 25MHz le Mehala ea Eona e le Maqhubu?

Hobaneng ha Lisebelisoa tsa Marang-rang li Sebelisa 25MHz le Mehala ea Eona e le Maqhubu?

Lisebelisoa tsa marang-rang tse kang likarete tsa marang-rang, li-switch, li-routers le lisebelisoa tsa Ethernet, khetho ea maqhubu a crystal oscillator e khethoa ke mesebetsi ea mantlha ea sesebelisoa, litlhoko tsa chip, le litekanyetso tsa protocol ea puisano. Tšebeliso ea li-oscillator tsa kristale tse nang le maqhubu a 25MHz le li-multiples tsa eona haholo-holo ka lebaka la tsamaiso ena ea maqhubu e haufi-ufi le litekanyetso tsa Ethernet, liprothokholo tsa puisano, le meralo ea li-chip, e nolofalletsang moralo o nolofalitsoeng, litšenyehelo tse fokotsehileng, le ts'ebetso e ntlafetseng. Ho fanoe ka tlhaloso e qaqileng ka tlase:

I. Hobaneng o Khetha 25MHz joalo ka Maqhubu a Base?

25MHz ha se boleng bo khethiloeng ka boomo. E sebelisoa haholo hobane e na le likamano tse ngata tse ngata tse nang le maqhubu a mangata a mantlha puisanong ea marang-rang, e thusang ho atisa kapa ho arola.

1.1 E Kopana le Litlhoko tsa Maqhubu a Maemo a Ethernet

Fast Ethernet (100BASE-TX): E sebelisa oache ea 25MHz joalo ka maqhubu a phetiso ea data.

Gigabit Ethernet (1000BASE-T): E sebelisa oache ea 125MHz, e leng 25MHz × 5.

10GbE (10 Gigabit Ethernet) le ka holimo: Le hoja maqhubu a oache a ka sehloohong a phahame (mohlala, 156.25MHz), hangata a ka fumanoa ka ho atisa oscillator ea kristale ea 25MHz ka PLL.

Sena se bontša hore 25MHz, joalo ka maqhubu a oache ea motheo, e ka tšehetsa ka kotloloho kapa ka mokhoa o sa tobang maqhubu a ts'ebetso a PHY/MAC bakeng sa lebelo le tloaelehileng la Ethernet.

II. Boikemisetso ba ho Kenngwa Tshebetsong

2.1 Easy Frequency Multiplication ka PLL

Lichipisi tsa netweke (tse kang PHY, MAC, le switch chips) hangata li sebelisa PLL (Phase Locked Loop) li-circuits ka hare ho hlahisa maqhubu a hlokahalang a oache ea ho sebetsa. 25MHz ke maqhubu a itekanetseng a kenyang a ka hlahisang -maqhubu a lebelo haholo, joalo ka:

25MHz × 2=50MHz

25MHz × 4=100MHz

25MHz × 5=125MHz

25MHz × 6.25=156.25MHz (bakeng sa 10GbE)

Kaha 25MHz ke lebelo la motheo le bonolo-ho{2}}ho bala palo e fokolang ea palo e fokolang, e nolofatsa moralo oa PLL, e nolofalletsa ho notlela kapele, le ho netefatsa tlhahiso e tsitsitseng haholoanyane.

2.2 E lumellana le Litlhoko tsa Mainstream Chip

Boholo ba baetsi ba lisebelisoa tsa marang-rang ba li-chip (joalo ka Broadcom, Realtek, Marvell, Intel, joalo-joalo) ba tšehetsa ka ho hlaka keno ea 25MHz crystal oscillator litlhoko tsa oache ea li-chips tsa PHY kapa MAC ea bona, kapa ba fana ka mekhoa ea ts'ebetso bakeng sa ho kenya 25MHz.

III. Melemo ho EMC, Moralo oa Potoloho, le Litšenyehelo

3.1 Taolo e ntle ea EMI le Botšepehi bo Phahameng ba Pontšo

Ha ho bapisoa le li-oscillator tsa kristale tse nang le maqhubu a holimo (mohlala, 50MHz, 100MHz, 125MHz, 150MHz, le 200MHz), 25MHz e fana ka melemo ea bohlokoa ho latela Phallo ea Motlakase (EMI):

Maqhubu a tlase a motheo a fella ka litšitiso tse fokolang tsa harmonic;

PCB routing e bonolo ho lumellana le litlhaloso tsa moralo oa EMI;

Litlhokahalo tse tlase bakeng sa lits'oants'o le botsitso ba matla, ho thusa ho kopanya tsamaiso.

3.2 Batho ba Holileng Pele, ba Tsitsitseng, le ba Litšenyehelo-Li-Crystal Oscillator tse Sebetsang

Li-oscillator tsa kristale tsa 25MHz ke tse ling tsa maqhubu a sebelisoang haholo indastering ea lisebelisoa tsa elektroniki, tse nang le melemo e latelang:

Ho na le{0}}lihlahisoa tsa{1}lihalalello tse ngata le mefuta e mengata e fapaneng;

Litšenyehelo tse tlase tsa tlhahiso le litheko tsa theko e tlase;

Ketane ea thepa e nang le nako e khuts'oane le boleng bo tsitsitseng.

Sena se khahla haholo baetsi ba lisebelisoa tsa marang-rang ba etsang-tlhahiso e kholo.

IV. Mohlala oa Tšebeliso ho Moralo o Sebetsang

Ho nka sesebelisoa sa Gigabit Ethernet joalo ka mohlala:

Chip e kholo ea taolo e hloka maqhubu a ts'ebetso ea ho kenya letsoho a 125MHz;

Moqaping, ho ka sebelisoa kristale oscillator ea 25MHz, 'me maqhubu a ka atolosoa ho 125MHz ka chip e hahiloeng{2}}ka PLL;

Ho sa le joalo, oache ea 25MHz e ka abeloa ho li-module tse ling (tse kang PHY, MAC, kapa li-module tsa synchronization tsa oache) ka sefate sa oache;

Sena se fihlella mohloli o kopaneng oa oache, se nolofatsa meralo ea oache, 'me se fokotsa ho rarahana ha sistimi le litšenyehelo.

Kakaretso

Mabaka a etsang hore lisebelisoa tsa marang-rang li sebelise 25MHz le li-multiples tsa eona joalo ka maqhubu a kristale oscillator li ka akaretsoa ka tsela e latelang:

Li-Oscillator tsa Hangjing Crystal li sebelisoa haholo lisebelisoa tsa marang-rang (likarete tsa marang-rang, li-switches, li-routers, Ethernet). Ho tlatselletsa lihlahisoa tsa boemo ba indasteri-, hape re fana ka-lithempereichara tse pharalletseng{3}}stability crystal oscillator (-55~{5}}℃) 'me re ka fana ka ts'ebeliso ea kristale oscillator le litharollo tse nyallanang. Haeba u na le litlhoko tse amehang, ka kopo ikutloe u lokolohile ho ikopanya le barekisi ba Hangjing kapa basebetsi ba tekheniki.