Ngā Tikanga Hoahoa Tātari Analog
I te ao hikohiko, he mea nui te mahi a ngā tātari anarohiko ki te hanga, ki te horoi, me te whakahaere i ngā irahiko tohu i mua i te tukatuka anō. Ahakoa te mana o te ao matihiko, he mea nui tonu ngā tātari anarohiko i roto i ngā tono maha—mai i te oro me ngā taputapu ki ngā whakawhitiwhiti kōrero ki ngā pūnaha whakahaere—nā te mea ka mahi i te wā tūturu me te kore e whakaroa te tukatuka, ā, ka taea te whakanoho ki te pito o mua o te ara iahiko hei pehi i te haruru mai i te tīmatanga. Ka matapakihia e tēnei tuhinga ngā tikanga hoahoa tātari anarohiko mahi: mai i ngā ariā taketake me te kōwhiringa āhuahanga ki ngā mahi hoahoa noa.
1. Te Ariā Taketake o ngā Tātari Analog
He ara iahiko te tātari anarohiko i hangaia hei tuku tohu i roto i tētahi awhe auau motuhake, hei whakaiti hoki i ngā auau i waho o taua awhe. I runga i tā rātou urupare auau, ka wehea ngā tātari anarohiko ki ētahi momo:
1. Tātari haere-iti (LPF): ka tukuna ngā auau iti, ka whakaiti i ngā auau teitei.
2. Tātari whakawhiti-teitei (HPF): ka tukuna ngā auau teitei, ka whakaiti i ngā auau iti.
3. Tātari whakawhiti-roopu (BPF): ka whiti i tētahi roopu auau, ka whakaiti i raro, i runga hoki i te roopu.
4. Tātari aukati-roopu/tātari notch: ka whakakore i ētahi roopu whaiti (hei tauira, 50/60 Hz).
5. Tātari katoa-haere: he āhua pumau te kaha, engari ka huri i te āhua (he pai mō te utu āhua).
Ko ngā tawhā matua o te tātari ko te auau tapahi (fc), te whakanui, te ripple (ngā ngaru iti i roto i te passband), te whakaiti i te stopband, me te raupapa tātari (e whakatau ana i te pari hurihuri). I te nuinga o te wā, ko te teitei ake o te raupapa, ko te koi ake o te whakawhiti, engari ko te uaua ake o te ara iahiko.
2. Whakatauhia ngā Whakatakotoranga Hoahoa
Ko ngā tikanga hoahoa pai ka tīmata tonu me ngā whakaritenga mārama. I mua i te whiriwhiri i tētahi āhuarangi, whakatauhia:
– Paenga-ā-pā: te awhe auau me pā, tae atu ki te ātete ripo.
– Ārai-ārai: te whānuitanga hei whakaiti, tae atu ki te ūnga whakaiti (hei tauira -40 dB).
– Auautanga whakawhiti: te tawhiti i waenga i ngā rohe o te awhi whakawhiti me te awhi aukati. Mēnā he whāiti ake, he teitei ake te raupapa e hiahiatia ana.
– Te ārai pūtake me te ārai kawenga: he mea nui mō ngā tātari kore mahi, hei karo hoki i te utaina.
– Ngā herenga wāhanga: te wātea o ngā uara R, C, te manawanui, te rahi, te utu, me ngā herenga op-amp (mō ngā tātari hohe).
Hei tauira, mō ngā tono oro, ka hiahia pea koe ki tētahi LPF me te 20 kHz fc, te iti o te ripple, me te iti o te distortion. Mō ngā taputapu, ka hiahia pea koe ki tētahi notch 50 Hz hei whakakore i te haruru hiko me te kore e whakararuraru i te tohu matua.
3. Te Kōwhiri i te Whakatata Urupare: Butterworth, Chebyshev, Bessel
Kāore e taea te whakatutuki i te urupare tātari tino pai, nō reira ka whakamahia te mahi whakatata paerewa:
– Butterworth: he papatahi te whānuitanga o te oro. He pai mō ngā mahi oro me ngā mahi whānui. Kāore te whakawhiti i te koi pērā i a Chebyshev i te raupapa kotahi.
– Chebyshev: he whakawhiti koi ake, engari he ripple kei roto i te passband (Chebyshev I) i te stopband rānei (Chebyshev II). He pai ina hiahiatia he whiriwhiringa teitei.
– Bessel: tata ki te rārangi te āhua, ā, he pai te urupare whakawhiti (he iti te rahinga). He pai mō ngā tohu pātere, ngā taputapu, me ētahi momo ārai-aliasing.
Ko te kōwhiringa o te whakatata ka whakawhirinaki ki te kaupapa matua: te whānuitanga papatahi, te whiriwhiri, te rārangi ā-wāhanga rānei.
4. Te Raupapa Tātari me te Hanganga Wāhanga (Te Whakahekenga)
Mā te raupapa tātari e whakatau te pikinga hurihuri: ka tāpirihia e ia raupapa tata ki te 20 dB/tekau tau (6 dB/octave rānei). Hei tauira, ka tāpirihia e te tātari raupapa tuarua tata ki te 40 dB/tekau tau. I roto i te mahi, ko ngā tātari raupapa teitei ake ka hangaia mā te whakarārangi i ētahi wāhanga raupapa tuatahi, tuarua rānei (biquad). Mā tēnei ka māmā ake te whakahāngai me te whiriwhiri i ngā wāhanga.
Ngā taahiraa whānui:
1. Whakatauhia te raupapa iti rawa o ngā whakatakotoranga whakaiti me te whakawhiti.
2. Wehea kia maha ngā wāhanga tuarua o te raupapatanga, + mēnā e tika ana kia kotahi te wāhanga tuatahi.
3. Whakatakotoria ngā tawhā mō ia wāhanga (Q me ω0) e ai ki te ripanga, ki ngā hua tātaitanga rānei.
5. Ngā Tātari Āhuakore, Ngā Tātari Kaha rānei
Tātari Whakakore
Ka whakamahia te R, L, me te C, kāore he whakakaha. Ngā Painga: he iti te haruru, kāore he pūtake hiko e hiahiatia ana, ka taea te mahi i ngā auau teitei. Ngā Huakore: he nui/he utu nui te inductor, he uta i waenga i ngā wāhanga, me te uaua ki te whiwhi whakanui.
E whakamahia whānuitia ana i roto i te RF, te taurite aukati, ngā tono mana teitei rānei.
Tātari Hohe
Te whakamahi i te op-amp + R me te C (kāore he inductor). Ngā painga: he iti ake te rahi, he ngāwari te whakahaere i te whiwhinga, he teitei te aukati tāuru me te iti o te aukati putanga. Ngā ngoikoretanga: he iti te whānui o te op-amp, he haruru op-amp, me te kaha o te saturation.
Mō ngā tohu oro me ngā tohu waenga-iti, ko ngā tātari hohe te kōwhiringa tuatahi.
6. Ngā Āhuatanga Tātari Hohe Noa
Ko ētahi o ngā āhuarangi rongonui:
1. Sallen-Key (VCVS)
He māmā te hoahoa, he iti noa ngā wāhanga, he pai mō te LPF/HPF tuarua. Ka pāngia a Q e te whakanui me te ōwehenga wāhanga. He maha ngā wā e whakamahia ana i roto i te oro.
2. Urupare Maha (MFB)
He pai mō te LPF/BPF me te Q teitei ake. He pumau ake mō te Q teitei i a Sallen-Key, engari he uaua ake te tatau i ngā wāhanga.
3. Taurangi Āhua / Tōia-Thomas
Ka whakaputa i ngā putanga LPF, HPF, me BPF i te wā kotahi. Ka ngāwari te whakarite i te auau Q me te auau oro. He pai mō ngā tātari ka taea te whakarerekē.
4. Biquad (whānui)
He kupu whānui mō tētahi poraka tuarua. He maha ngā tātari teitei ake i hangaia mai i ngā biquad.
Ko te kōwhiringa o te āhuarangi ka pāngia e ngā whakaritenga Q, te ngāwari o te whakahāngai, te aro ki te manawanui, me ngā āhuatanga o te op-amp.
7. Ngā Tikanga Hoahoa Whaihua (Rerenga Mahi)
Koinei te tukanga mahi e whakamahia whānuitia ana i roto i te hoahoa i ngā tātari anaro:
1. Whakatauhia ngā whakaritenga: momo tātari, fc/fo, ripple, attenuation, raupapa.
2. Tīpakohia te whakatata: Butterworth/Chebyshev/Bessel.
3. Tikina ngā tawhā wāhanga: ω0 me Q mō ia biquad (mai i ngā ripanga, pūmanawa, tātai rānei).
4. Tīpakohia he āhua mō ia wāhanga: Sallen-Key mō te Q waenga, MFB mō te Q teitei, state-variance mō te whakahāngai.
5. Tātaihia te uara o te wāhanga: tautuhia te paerewa C i te tuatahi (hei tauira, 10 nF, 100 nF) kātahi ka tātaihia te R kia māmā ake ai te tika.
6. Whakatauira: whakamahia te SPICE hei tiro i te rahi me te urupare ā-wāhanga, tirohia hoki te mākū me te haruru o te op-amp.
7. Whakaarohia te manawanui: Ka taea e R 1% me C 5% te neke i te fc me te Q. Mō ngā tono tika, whakamahia te manawanui C 2%, te kuti rānei.
8. Tahora PCB: whakaitihia ngā ara roa, wehea ngā whenua anaro, karohia te hononga, ā, whakanohoia ngā pūnga tata ki te op-amp.
9. Whakamātautau tauira: ine i te urupare auau (tātari), tirohia te whakapōturitanga (THD mō te oro), me te whakamana i ngā rerekētanga pāmahana.
8. Ngā Āhuatanga Kāore i te Pai e Hiahiatia Ana
Ka pāngia ngā tātari anaro tūturu e:
– Te whānui o te op-amp (GBW): mō te Q teitei me ngā auau teitei, me nui ake te GBW o te op-amp i te auau whakahaere.
– Te tere o te oro: ka taea e ngā tohu whānui nui i ngā auau teitei te whakapōturi i te oro.
– Haruru: Ka tāpirihia he haruru e ngā ātete me ngā op-amp. I roto i ngā taputapu, arotauhia ngā uara ātete, ā, whiriwhiria ngā op-amp haruru iti.
– Ngā ātete wāhanga: He tino tairongo a Q; mā ngā hoahoa "pakari" ka karohia ngā Q tino nui mēnā kāore e tika ana.
– Te uta i waenga i ngā wāhanga: kia whakarite kia āraihia, kia whakamahia rānei he āhua e whakaiti ana i te taunekeneke.
Mā te whai whakaaro ki ngā āhuatanga kāore i te tino pai mai i te tīmatanga, ka rite ake te hua whakamutunga ki ngā tumanakohanga ina tutuki.
9. Ngā Tauira Taupānga
– Whakawhiti oro: ka whakamahia te LPF me te HPF o te raupapa 2–4 hei wehewehe i ngā auau ki te tweeter me te woofer.
– Ārai-aliasing: LPF i mua i te ADC hei ārai i ngā wāhanga auau teitei kei takai ki te haruru.
– Notch 50/60 Hz: hei whakakore i te haruru i ngā tohu ECG/EEG, i ngā pūoko ahumahi rānei.
– Te pito-mua RF: te whakawhiti-roopu whaiti hei tīpako i tētahi hongere motuhake.
Whakamutunga
Ko ngā tikanga hoahoa tātari anarohiko ko te whiriwhiri i ngā whakatakotoranga, te whakatata urupare (Butterworth, Chebyshev, Bessel), te whakatau raupapa, te whiriwhiri āhuarangi (Sallen-Key, MFB, taurangi-āhua), me te aromatawai i ngā āhuatanga kore-tino pai pērā i ngā manawanui wāhanga me ngā herenga op-amp. Mā te rere hoahoa pūnaha me te whakatauira pai, ka taea te hanga i ngā tātari anarohiko kia tika, kia pumau, kia rite ki ngā hiahia tono—ahakoa mō te oro, te taputapu, te whakawhitiwhiti kōrero rānei.
Ki te hiahia koe, ka taea e au te āwhina i a koe ki te waihanga i tētahi tauira tatau katoa (hei tauira, he Butterworth LPF tuawhā me te āhuahanga Sallen-Key) me ngā uara RC me ngā hua whakatauira ariā.
