Molao-motheo oa ho Sebetsa oa Li-Oscillator ho Elektroniki
Sesebediswa sa ho sisinyeha ke e 'ngoe ea lipotoloho tsa bohlokoa ka ho fetisisa tsa elektronike hobane se hlahisa matšoao a nako le nako ka boikemelo ntle le tlhoko ea ho kenngoa ha motlakase o tsoang kantle (AC). Hoo e ka bang lisebelisoa tsohle tsa sejoale-joale li sebelisa li-oscillator, ho tloha lioacheng tsa dijithale le li-radio ho ea ho liselefouno le lik'homphieutha ho ea ho litsamaiso tsa puisano tsa sathelaete. Ka mantsoe a mang, sesebediswa sa ho sisinyeha se ka nkoa e le "pelo" ea potoloho, se fanang ka li-pulse tsa matšoao tse pheta-phetoang ho laola nako (oache), ho jara tlhahisoleseling, kapa ho hlahisa maqhubu a carrier. Sengoloa sena se tšohla melao-motheo ea ts'ebetso ea li-oscillator, likarolo tsa tsona, le mefuta ea li-oscillator tse sebelisoang hangata.
Ho utloisisa li-oscillator
Ka bokhutšoanyane, oscillator ke potoloho ea elektroniki e hlahisang sebopeho sa maqhubu a motlakase a nako le nako, joalo ka leqhubu la sine, sekwere, khutlotharo, kapa sawtooth. Tšobotsi e ka sehloohong ea oscillator ke bokhoni ba eona ba ho hlahisa lets'oao le pheta-phetoang khafetsa ka maqhubu a itseng. Maqhubu ana a ka ba tlase haholo (mohlala, Hertz tse 'maloa) ho isa ho holimo haholo (GHz), ho latela litlhoko tsa ts'ebeliso.
Li-oscillator li fapana le li-amplifier tse tloaelehileng. Li-amplifier li hloka lets'oao la ho kenya ho holisa, ha li-oscillator li "iketsetsa" lets'oao la tsona ka mekhoa ea ho fana ka maikutlo le maemo a itseng a bakang ho sisinyeha.
Khopolo ea Motheo: Maikutlo a Matle
Molao-motheo oa bohlokoa ka ho fetisisa ho li-oscillator ke karabelo e ntle. Potolohong ea amplifier, karolo ea lets'oao la tlhahiso e nkuoa ebe e khutlisetsoa ho kenyelletso. Haeba lets'oao le khutlisitsoeng le le mohatong o nang le kenyelletso, karabelo e bitsoa e ntle. Maikutlo a matle a eketsa lets'oao, 'me haeba maemo a finyelloa, lets'oao le tla hola ho ba pherekano e tsitsitseng.
Ha e le hantle, di-oscillator hoo e ka bang kamehla di sebedisa karolo ya ho hodisa (transistor, op-amp, kapa vacuum tube ditheknolojing tsa kgale) hammoho le netweke e kgethang ya maikutlo e etsang qeto ya maqhubu.
Maemo a ho Etsahala ha ho Tsitsinyeha (Barkhausen Criterion)
E le hore oscillator e sisinyehe, hangata ho sebelisoa litekanyetso tsa Barkhausen, e leng maemo a mabeli a mantlha:
1. Maemo a bophahamo (phaello ea selika-likoe):
Phaello ea loop e lokela ho lekana le 1 kapa e be kholo ho feta 1 hanyane ha k'hamphani e qala.
\|Aβ\| ≥ 1
Mona A ke keketseho ea amplifier, ha β e le ntlha ea karabelo.
2. Litlhoko tsa Mokhahlelo:
Phetoho yohle ya mokgahlelo tseleng ya sekgoqetsane e lokela ho ba 0° kapa palo e ngata ya 360°. Sena se bolela hore letshwao le kgutlelang ho keno le tlameha ho ba mokgahlelong le letshwao la keno.
Haeba maemo ana a mabeli a finyelloa, lets'oao le lenyenyane (hangata le tsoang lerata la mocheso la karolo) le tla holisoa khafetsa ho fihlela le fihla boemong bo tsitsitseng.
Mekhahlelo ea ho Sebetsa ea Oscillator
1. Qalo (Qala ho sisinyeha)
Ha potoloho e qala ho sebetsa, ha ho na lets'oao la ho kenya. Leha ho le jwalo, kamehla ho na le lerata le itseng ka hare ho dikarolo. Lerata lena le kena ho amplifier mme le atoloswa. Haeba ka maqhubu a itseng marangrang a maikutlo a fihlela ditlhoko tsa mohato le boholo ba motlakase, karolo eo ya maqhubu e tla ba matla mme e tswele pele ho hola.
2. Ho eketsa le ho khetha maqhubu
Marangrang a ditshwaelo hangata a kgetha, ho bolelang hore a dumella maqhubu a itseng feela ho fumana maikutlo a nepahetseng a nepahetseng. Ka lebaka leo, oscillator e tla sebetsa maqhubung ao, ha maqhubu a mang a tla fokotswa.
3. Ho tsitsisa bophahamo ba amplitude (boemo bo tsitsitseng)
Haeba keketseho ea loop e tsoela pele ho ba kholo ho feta 1, boholo ba amplitude bo tla tsoela pele ho eketseha ho fihlela potoloho e kolobile 'me e ba le ho sotha ho hoholo. Ho hlahisa tlhahiso e tsitsitseng, oscillator e hloka mokhoa o fokotsang amplitude kapa oa taolo, mohlala:
– Ho se latele tsela ya tlhaho ya di-transistors/op-amps,
– Tšebeliso ea li-diode tse fokotsang,
– Lebone le lenyenyane la incandescent (ho oscillator ea khale ea Wien Bridge),
– AGC (Taolo ea ho Fumana ka Boiketsetso) ho li-oscillator tse itseng.
Sebakeng se tsitsitseng, keketseho e sebetsang ea loop e ba hoo e ka bang 1 hoo amplitude e sa eketseheng kapa e fokotsehang.
Likarolo tse Fumanang Maqhubu
Hangata maqhubu a ho sisinyeha a khethoa ke marang-rang a khethollang maqhubu, mohlala:
1. RC (Mohanyetsi-Motlakase)
E loketse maqhubu a tlase ho isa bohareng (molumo o fihlang ho makholo a kHz).
2. LC (Motlakase oa Inductor)
E tloaelehileng bakeng sa maqhubu a seea-le-moea (makholo a kHz ho isa ho mashome a MHz).
3. Kristale (kristale ea quartz)
E fana ka botsitso bo phahameng haholo ba maqhubu, e leng ntho e tloaelehileng bakeng sa lioache tsa microcontroller, lik'homphieutha le puisano.
Ha karolo e khethollang maqhubu e tsitsitse haholoanyane, tlhahiso ea oscillator e tla ba e tsitsitseng haholoanyane khahlanong le liphetoho tsa mocheso, motlakase le litšitiso tsa mojaro.
Mefuta e Tloaelehileng ea Li-Oscillator
1. Sehokelo sa RC
Li-oscillator tsa RC li sebelisa motsoako oa li-resistor le li-capacitor ho hlahisa phetoho e itseng ea mohato.
a. Oscillator ea Phase ea RC
Ka ho sebelisa mekhahlelo e mengata ea RC e nang le phetoho e felletseng ea mohato oa 180°, amplifier e kenang e eketsoa ho fana ka 180° e 'ngoe bakeng sa kakaretso ea 360°. E loketse ho hlahisa maqhubu a sine maqhubung a molumo.
b. Sesebediswa sa ho tjhesa sa Borokho ba Vienna
E 'ngoe ea li-oscillator tse tsebahalang haholo tsa sine. E sebelisa borokho ba Wien (motsoako oa li-circuits tsa letoto le tse tsamaeang ka tsela e tšoanang) ho fumana maqhubu. Molemo oa eona ke ho sotha ho tlase haeba amplitude e laoloa hantle, mohlala, ka ho sebelisa lebone la incandescent e le karolo ea taolo ea gain.
2. Sehokelo sa LC
Sesebediswa sa ho sisinyeha sa LC se hlahisa ho sisinyeha ho ipapisitseng le molumo wa potoloho ya inductor (L) le capacitor (C). Lebelo le loketseng la ho sisinyeha ke:
\[
f = \frac{1}{2\pi\sqrt{LC}}
\]
Mefuta e tsebahalang:
– Hartley Oscillator: e sebedisa di-tap hodima inductor kapa di-inductor tse pedi ka tatellano.
– Colpitts Oscillator: e sebelisa karohano ea capacitor (li-capacitor tse peli ka tatellano).
– Clapp Oscillator: mofuta o fapaneng wa Colpitts o nang le capacitor e eketsehileng bakeng sa botsitso.
Li-oscillator tsa LC li sebelisoa haholo ho li-radio transmitters, li-receiver, li-VCO (Li-Voltage Controlled Oscillators), le lipotoloho tse ling tsa RF.
3. Osilator Kristal
Li-oscillator tsa kristale li sebelisa molumo oa mechine oa kristale ea quartz e bohale haholo (e phahameng-Q). Ka hona, maqhubu a tsona a nepahetse haholo ebile a tsitsitse. Likristale tse tloaelehileng li fumaneha ka 32.768 kHz (oache), 8 MHz, 16 MHz, 25 MHz, le litekanyetso tse ling tse ngata.
Ketello:
– Ho tsitsa ha maqhubu a phahameng,
– Lerata le tlase la mohato ha le bapiswa le RC/LC e tloaelehileng.
Khaello:
– Maqhubu ha a bonolo ho a fetola,
– Hloka potoloho e loketseng ea mokhanni e le hore kristale e se ke ea khanna ho feta tekano.
4. Sesupa-nako sa ho phomola
Ho fapana le oscillator ea leqhubu la sine, oscillator ea phomolo e hlahisa maqhubu a seng a sine (a sekwere, a khutlotharo, a sawtooth) ka ho tjhaja le ho ntsha capacitor khafetsa. Mohlala:
– Se-multivibrator se tsitsitseng (transistor kapa se thehiloeng ho IC 555),
– Oscillator e thehiloeng ho Schmitt trigger.
Sesebediswa sena sa ho sisinyeha se tumme bakeng sa dijenereithara tsa pulse, di-timers, PWM, le dipotoloho tsa dijithale.
Lintlha tsa Bohlokoa Moralong oa Oscillator
1. Botsitso ba maqhubu
E angoa ke mamello ea likarolo, mocheso, botsofali le liphetoho tsa motlakase. Bakeng sa litsamaiso tse nepahetseng, likristale kapa TCXO/OCXO hangata lia khethoa.
2. Lerata la mokhahlelo le ho thothomela
E bohlokoa haholo litsamaisong tsa puisano tsa dijithale le oache. Lerata le phahameng la mokgahlelo le ka senya boleng ba modulation, la eketsa BER (Bit Error Rate), le ho sotha spectrum.
3. Ho sotha maqhubu
Ho molemo hore oscillator ea sine e be le ho sotha ho tlase. Ho sotha ho etsahala haeba taolo ea amplitude e le mpe kapa amplifier e sebetsa sebakeng se seng sa mola.
4. Phello ea mojaro (ho kenya)
Haeba tlhahiso e kentswe ka ho toba, marangrang a resonance a ka fetoha, e leng se etsang hore maqhubu a fetohe. Ka hona, li-buffer (balateli ba emitter, li-buffer tsa op-amp) hangata li sebelisoa ho "arola" potoloho e khethollang maqhubu.
Qetello
Molao-motheo o sebetsang oa oscillator ka har'a lisebelisoa tsa elektroniki o itšetlehile ka maikutlo a matle le ho phethahala ha tekanyetso ea Barkhausen: keketseho e lekaneng ea loop le phetoho e felletseng ea mohato oa 0°/360°. Oscillator e qala ho sisinyeha ho tsoa lerata la kahare, ebe marang-rang a khethollang maqhubu (RC, LC, kapa kristale) a khetha maqhubu a itseng, 'me qetellong amplitude e tsitsisoa ke mokhoa o fokotsang keketseho. Mefuta e fapaneng ea li-oscillator—RC, LC, kristale, le phomolo—li khethoa ho latela maqhubu, botsitso, sebopeho sa maqhubu le litlhoko tsa ts'ebeliso. Ho utloisisa melao-motheo ena ho thusa baenjiniere le baithuti ba lisebelisoa tsa elektroniki ho rala litsamaiso tse tšepahalang tsa oache, lijenereithara tsa matšoao le lipotoloho tsa puisano.
Haeba o batla, nka eketsa mohlala oa palo ea maqhubu bakeng sa e 'ngoe ea mefuta ea oscillator (mohlala, Wien Bridge kapa Colpitts) hammoho le moralo oa potoloho ea motheo.
