Te Mātāpono Mahi a ngā Oscillators i roto i te Hikohiko
Ko te oscillator tētahi o ngā ara iahiko tino nui o te hikohiko nā te mea ka whakaputa motuhake i ngā tohu ā-wā, me te kore e hiahiatia he tāurunga aukume tauutuutu (AC) o waho. Tata ki ngā taputapu hou katoa e whakamahi ana i ngā oscillator, mai i ngā karaka mamati me ngā reo irirangi ki ngā waea pūkoro me ngā rorohiko ki ngā pūnaha whakawhitiwhiti amiorangi. Arā, ka taea te whakaaro ko te oscillator te "ngakau" o tētahi ara iahiko, e whakarato ana i ngā pāorooro tohu auau hei whakahaere i te wā (karaka), hei kawe i ngā mōhiohio, hei whakaputa rānei i ngā ngaru kawe. Ka matapakihia e tēnei tuhinga ngā mātāpono mahi o ngā oscillator, ō rātou wāhanga, me ngā momo oscillator e whakamahia whānuitia ana.
Te Mārama ki ngā Oscillators
I te whakarapopototanga, he ara iahiko hiko te oscillator e whakaputa ana i tētahi ngaru hiko ā-wā, pērā i te sine, te tapawhā, te tapatoru, te ngaru niho kani rānei. Ko te āhuatanga matua o tētahi oscillator ko tōna kaha ki te whakaputa i tētahi tohu e pūmau tonu ana i tētahi auau motuhake. Ka taea e tēnei auau te tino iti (hei tauira, he torutoru Hertz) ki te tino teitei (GHz), i runga i ngā whakaritenga tono.
He rerekē ngā oscillator i ngā whakakaha oro tuku iho. Me whai tohu tāuru ngā whakakaha hei whakakaha, ko ngā oscillator ia ka "waihanga" i ā rātou ake tohu mā roto i ngā tikanga urupare me ētahi āhuatanga e whakaoho ana i te oscillation.
Ariā Taketake: Urupare Pai
Ko te kaupapa matua o ngā oscillator ko te urupare pai. I roto i te ara iahiko whakakaha, ka tangohia tetahi wāhanga o te tohu putanga ka whakahokia ki te tāuru. Mena kei te ōrite te āhua o te tohu i whakahokia mai ki te tāuru, ka kiia te urupare pai. Ka whakanuia e te urupare pai te tohu, ā, ki te tutuki ngā tikanga, ka tipu te tohu hei oscillation pumau.
I roto i te mahi, he maha tonu ngā wā ka whakamahia e ngā oscillator tētahi huānga whakakaha (transistor, op-amp, ngongo korehau rānei i ngā hangarau tawhito) me tētahi whatunga urupare whiriwhiri e whakatau ana i te auau.
Ngā Tikanga mō te Puta o te Oscillation (Paerewa Barkhausen)
Kia taea ai e te oscillator te oscillate, ka whakamahia ngā paearu Barkhausen, arā, e rua ngā āhuatanga matua:
1. Ngā āhuatanga o te whānui (te whakanui i te porowhita):
Me ōrite te whakanui i te koropiko ki te 1, kia paku nui ake rānei i te 1 i te tīmatanga. Mā te pāngarau:
\|Aβ\| ≥ 1
Ko A te whakanui i te kaha whakakaha, ko β ia te tauwehe urupare.
2. Ngā whakaritenga wāhanga:
Me 0° te nekehanga ā-wāhanga katoa i te ara porowhita, me tauwehe rānei i te 360°. Ko te tikanga me rite te ā-wāhanga o te tohu e hoki ana ki te tāuru ki te tohu tāuru.
Mena ka tutuki ēnei tikanga e rua, ka whakanuia tonutia he tohu iti (e ahu mai ana i te haruru wera o te wāhanga) kia tae rā anō ki tētahi āhua pumau.
Ngā Wāhanga Mahi a te Oscillator
1. Tīmatanga (Tīmata ki te wiri)
Ina whakakahangia te ara iahiko mō te wā tuatahi, kāore he tohu tāuru. Heoi anō, he haruru tonu kei roto i ngā wāhanga. Ka uru tēnei haruru ki te whakakaha, ā, ka whakanuia. Mena ka tutuki i te whatunga urupare ngā whakaritenga o te wāhanga me te kaha, i tētahi auau, ka noho hei wāhanga matua taua auau, ā, ka tipu tonu.
2. Te whakanui me te whiriwhiri i te auau
He mea whiriwhiri ngā whatunga urupare, arā, ko ētahi auau anake ka whakaaetia kia whiwhi i te urupare pai tika. Nō reira, ka mahi te oscillator i aua auau, ko ētahi atu auau ka whakaitihia.
3. Te whakapūmau i te kaha (āhua pumau)
Ki te nui ake tonu te whakanui o te koropiko i te 1, ka piki tonu te kaha o te oro tae noa ki te kī o te ara iahiko, ā, ka pāngia e te hē nui. Hei whakaputa i tētahi putanga pumau, me whai tikanga whakawhāiti kaha, tikanga whakahaere rānei te oscillator, hei tauira:
– Te kore-rārangi tūturu o ngā transistors/op-amps,
– Te whakamahinga o ngā diode whakawhāiti,
– Rama mura iti (i runga i te ohihuri Wien Bridge matarohia),
– AGC (Mana Whakanui Aunoa) i runga i ētahi orooro.
I te pūwāhi pumau, ka tata tonu te hua whai hua o te koropiko ki te 1, kia kore ai te kaha e piki ake, e heke iho rānei.
Ngā Huānga Whakatau Auautanga
Ko te auau o te wiri ka whakatauhia e te whatunga whakatau auau, hei tauira:
1. RC (Ātete-Pūnga)
He pai mō ngā auau iti ki waenga (oro tae atu ki ngā rau kHz).
2. LC (Inductor-Capacitor)
He mea noa mō ngā auau reo irirangi (rau o kHz ki ngā tekau o MHz).
3. Kiriata (kiriata quartz)
E whakarato ana i te pumau auau tino teitei, he mea noa mō ngā karaka pūmana iti, ngā rorohiko, me ngā whakawhitiwhiti kōrero.
Ka nui ake te pumau o te huānga whakatau auau, ka nui ake te pumau o te putanga o te oscillator ki ngā huringa o te pāmahana, te ngaohiko me te raruraru kawenga.
Ngā Momo Noa o ngā Oscillators
1. RC Oscillator
Ka whakamahia e ngā oscillator RC te huinga o ngā ātete me ngā pūnga hei whakaputa i tētahi nekehanga ā-wāhanga motuhake.
a. RC Āmiomio Nekehanga Āhuatanga
Mā te whakamahi i ngā wāhanga RC maha me te nekehanga wāhanga katoa o te 180°, ka tāpirihia he whakakaha whakahuri hei whakarato i tētahi atu 180°, arā, ko te tapeke o te 360°. He pai mō te whakaputa ngaru sine i ngā auau oro.
b. Te Āmiomio o te Piriti o Wien
Ko tētahi o ngā oscillator sine rongonui. Ka whakamahia he piriti Wien (he huinga o ngā ara iahiko RC raupapa me te ara iahiko RC whakarara) hei whakatau i te auau. Ko tōna painga he iti te whakapōturi mena ka pai te whakahaere i te kaha, hei tauira, mā te whakamahi i te rama mura hei wāhanga whakahaere whakanui.
2. LC Oscillator
Ka whakaputahia e te oscillator LC ngā oscillation i runga i te haruru o te ara iahiko inductor (L) me te capacitor (C). Ko te auau haruru pai rawa atu ko:
\[
f = \frac{1}{2\pi\sqrt{LC}}
\]
Ngā momo rongonui:
– Hartley Oscillator: ka whakamahia ngā pato ki runga i tētahi inductor, i ētahi inductor e rua rānei e raupapa ana.
– Colpitts Oscillator: e whakamahi ana i tētahi wehewehe pūnga (e rua ngā pūnga e raupapa ana).
– Clapp Oscillator: he momo rerekē o te Colpitts me tētahi pūnga taapiri hei pumau.
E whakamahia whānuitia ana ngā oscillators LC i roto i ngā tuku reo irirangi, ngā kaiwhiwhi, ngā VCO (Voltage Controlled Oscillators), me ētahi atu ara iahiko RF.
3. Te Oscillator Karaihe
Ka whakamahia e ngā orooro karaihe te haruru ā-pūkaha o tētahi karaihe kuata tino koi (Q-teitei). Nō reira, he tino tika, he pumau hoki tō rātou auau. Kei te wātea ngā tioata noa i roto i te 32.768 kHz (karaka), 8 MHz, 16 MHz, 25 MHz, me te maha atu o ngā uara.
Te taikaha:
– Te pumau o te auau teitei,
– He iti te haruru ā-wāhanga ki te whakataurite ki te RC/LC noa.
Te korenga:
– Ehara i te mea ngāwari te whakarerekē i te auau,
– Me whai ara iahiko taraiwa e tika ana kia kore ai te karaihe e tere rawa.
4. Oscillator Whakangā
He rerekē tēnei i te oscillator ngaru sine, ka puta i te oscillator whakangā ngā ngaru kore-sine (tapawhā, tapatoru, niho kani) mā te utu me te tuku i te pūnga iahiko. Hei tauira:
– He maha-wiri astable (e hangai ana ki te transistor, ki te IC 555 rānei),
– Te ohiroa e hangai ana ki te whakaoho a Schmitt.
He rongonui tēnei oscillator mō ngā whakaputa pātere, ngā taima, te PWM, me ngā ara iahiko mamati.
Ngā Take Hiranga i roto i te Hoahoa o te Oscillator
1. Te pumau o te auau
Ka pāngia e ngā ātete o ngā wāhanga, te pāmahana, te koroheketanga, me ngā rerekētanga ngaohiko. Mō ngā pūnaha tino tika, ka whiriwhiria pinepinetia ngā tioata, ngā TCXO/OCXO rānei.
2. Haruru ā-wāhanga me te wiri
He mea tino nui tēnei i roto i ngā pūnaha whakawhitiwhiti matihiko me ngā pūnaha karaka. Ka taea e te haruru ā-wāhanga teitei te whakaiti i te kounga o te whakarerekētanga, te whakanui ake i te BER (Bit Error Rate), me te whakapohehe i te whānuitanga.
3. Te whakapōturitanga o te ngaru
Ko te tumanako, he iti te whakapōturitanga o te oscillator sine. Ka puta te whakapōturitanga mēnā he ngoikore te whakahaere o te kaha, mēnā rānei kei te mahi te whakakaha i roto i tētahi rohe kore-raina.
4. Te pānga o te kawenga (uta)
Mena ka utaina tika te putanga, ka taea te huri i te whatunga orooro, ka huri te auau. Nō reira, he maha ngā wā ka whakamahia ngā arai (ngā kaiwhai emitter, ngā arai op-amp) hei "wehewehe" i te ara iahiko whakatau auau.
Whakamutunga
Ko te mātāpono mahi o tētahi oscillator i roto i te hikohiko e whakawhirinaki ana ki te urupare pai me te whakatutukitanga o te paearu Barkhausen: te whakanui i te porowhita me te nekehanga ā-wāhanga katoa o te 0°/360°. Ka tīmatahia e te oscillator ngā oscillation mai i te haruru o roto, kātahi ka tīpakohia e te whatunga whakatau-auau (RC, LC, tioata rānei) tētahi auau motuhake, ā, hei whakamutunga ka whakapūmauhia te kaha e tētahi tikanga whakawhāiti-whakanui. Ka tīpakohia ngā momo oscillator—RC, LC, tioata, me te whakangā—i runga i te auau, te pumau, te āhua ngaru, me ngā whakaritenga tono. Mā te mārama ki ēnei mātāpono ka āwhina i ngā kaihangarau me ngā ākonga hikohiko ki te hoahoa i ngā pūnaha karaka pono, ngā kaihanga tohu, me ngā ara iahiko whakawhitiwhiti kōrero.
Ki te hiahia koe, ka taea e au te tāpiri i tētahi tauira o te tatau auau mō tētahi o ngā momo oscillator (hei tauira, Wien Bridge, Colpitts rānei) me te hoahoa ara iahiko taketake.
