1.CVC da DSP rage surutu:
Lokacin da masu amfani suka sayi na'urar kai ta Bluetooth, koyaushe za su ji ayyukan rage amo na CVC da DSP waɗanda 'yan kasuwa ke da shi wajen haɓaka belun kunne. Komai yawan masu amfani da suka ji kwatancen, yawancin masu amfani har yanzu ba su fahimci bambanci tsakanin su biyun ba. Bambanci, don irin wannan matsala ta fasaha, mun zo ilimin kimiyya na biyu a ƙarƙashin ka'idar aiki da bambanci.
DSP gajeriyar hannu ce don sarrafa siginar dijital. Ka'idar aikinsa: makirufo yana tattara hayaniyar muhalli na waje, sannan ta hanyar tsarin rage amo yana aiki a cikin belun kunne, yana kwaikwayi don samar da raƙuman sauti mai jujjuya daidai da amo na yanayi, wanda ke soke amo kuma don haka ya sami ƙari. Kyakkyawan tasirin rage amo.
CVC gajarta ce don Bayyanar Murya. Fasaha ce ta rage hayaniyar software. Ka'idar ita ce murkushe nau'ikan amo daban-daban ta hanyar ginanniyar software na soke amo da makirufo.
Bambancin kamar haka:
a. don abu ya bambanta, fasahar CVC ya fi dacewa don amsawar da aka yi a lokacin kira, DSP ya fi dacewa don ƙarar ƙararrawa da ƙananan ƙararraki a cikin yanayin waje.
b. masu amfana daban-daban, fasahar DSP ta fi sa masu amfani da lasifikan kai samun kudin shiga na sirri, kuma CVC galibi suna amfanar ɗayan.
A taƙaice, belun kunne ta amfani da fasahar rage amo ta DSP da CVC na iya rage hayaniyar waje na kiran yadda ya kamata, da kuma inganta ingancin kiran da kuma sautin belun kunne.
2.ANC rage surutu:
ANC tana nufin Kula da Surutu Mai Aiki, wanda ke rage hayaniya sosai. Ka'ida ta asali ita ce tsarin rage amo yana haifar da raƙuman sauti mai jujjuya daidai da hayaniyar waje, yana kawar da amo. Hoto 1 siffa ce ta tsararraki na amo mai faɗakarwa mai aiki tana soke belun kunne. Ana sanya guntu ANC a cikin belun kunne. Ref mic (makirfon tunani) yana tattara hayaniyar yanayi akan belun kunne. Kuskuren mic (Kuskuren Makirufo) Yana tattara ragowar hayaniyar bayan rage amo a cikin kunnen kunne. Kakakin yana kunna hayaniyar bayan sarrafa ANC.
Hoto na 2 zane ne na tsarin ANC, tare da yadudduka uku, waɗanda aka raba su ta hanyar layukan da aka yanke. Hanya mafi girma ta farko ita ce tashar sauti daga ref mic zuwa kuskure mic, aikin amsa yana wakilta ta P(z) P(z); tsakiyar Layer shine tashar analog, inda hanya ta biyu ita ce hanya daga fitarwar tacewa mai daidaitawa zuwa ragowar dawowa. Ciki har da DAC, matatar sake ginawa, amplifier wutar lantarki, sake kunnawa lasifikar, sake-saye, pre-amplifier, tacewa mai hanawa, ADC; Layer na ƙasa shine hanyar dijital, inda tace mai daidaitawa koyaushe yana daidaita ƙimar ƙimar tace don rage ragowar har zuwa haɗuwa. Mafi na kowa bayani shine aiwatar da tace mai daidaitawa ta amfani da matatar FIR a hade tare da algorithm na LMS. Sauƙaƙe Hoto 2 kuma sami Hoto na 3.
Bari in yi magana a taƙaice game da ƙa'idodin filtatar daidaitawa da LMS (Mafi ƙanƙantar murabba'i) algorithm, sannan Hoto 3. Kamar yadda aka nuna a hoto na 4, da aka ba da shigarwar xx da abin da ake so dd, tace mai daidaitawa yana sabunta ƙididdiga ta kowane juzu'i don haka. Bambanci tsakanin fitarwa yy da dd ya zama ƙarami kuma ƙarami har sai ragowar ya kusa isa zuwa sifili kuma ya haɗu. LMS shine sabunta algorithm don masu tacewa. Manufar aikin LMS shine murabba'in kuskuren nan take e2(n)=(d(n)-y(n))2e2(n)=(d(n)−y(n))2,domin rage girman Haƙiƙa aikin, Aiwatar da zuriyar gradient yana ba da ingantaccen tsarin algorithm. (Ra'ayin algorithmic na yin amfani da zuriyar gradient don rage maƙasudi da samun ingantaccen tsarin siga da ake nema ya zama ruwan dare gama gari, kamar koma bayan layin layi.) Ƙididdiga na sabunta tsarin LMS algorithm ta amfani da tace FIR shine: w(n+1). ) = w(n)+μe(n)x(n)w(n+1)=w(n)+μe(n)x(n), inda μμ yake girman mataki. Idan an daidaita girman μμ tare da maimaitawa, matakin LMS algorithm ne na mataki-mataki.
Bari mu yi magana game da Hoto na 3. Anan ana fitar da tace mai daidaitawa bayan S(z) S (z) don kwatanta da fitarwar sha'awa. S(z)S(z) zai haifar da rashin kwanciyar hankali. A cikin wallafe-wallafen, "siginar kuskure ba a daidaita shi daidai ba" A cikin lokaci tare da siginar tunani", haɗin LMS ya karye. (Ban gano abin da ake nufi da T__T ba) Hanya mai tasiri ita ce FXLMS (Filtered-X LMS), wanda ke ba da damar x (n) don shigar da tsarin LMS ta hanyar Sˆ (z) S ^ (z), Sˆ ( z S^(z) kimanta S(z) S(z) Manufar FXLMS:
E2(n)=(d(n)-s(n)∗[wT(n)x(n)])2,
E2(n)=(d(n)-s(n)∗[wT(n)x(n)])2,
Don haka gradient = -2e (n) s (n) ∗x (n) -2e (n) s (n) ∗x (n), inda s (n) s (n) ba a san shi ba, tare da kimantawa, don haka FXLMS Sabunta dabarar shine
w(n+1)=w(n)+μe(n)x'(n),
w(n+1)=w(n)+μe(n)x'(n),
inda x'(n)=sˆ(n)∗x(n)x'(n)=s^(n)∗x(n).
Lokacin da matatar daidaitawa ta haɗu, E (z) = X (z) P (z) -X (z) W (z) S (z) ≈0E (z) = X (z) P (z) -X(z) ) W(z) S(z) ≈ 0, haka W(z) ≈ P(z) / S(z) W(z) ≈ P(z) / S(z). Wato, ma'aunin nauyi na tace mai daidaitawa yana ƙaddara ta hanyar farko da kuma hanyar sakandare na belun kunne. Hanya ta farko da hanyar na biyu na lasifikan kai suna da ingantacciyar tsayayye, don haka ma'aunin nauyi na tace mai daidaitawa yana da inganci. Sabili da haka, saboda sauƙi, ana ƙaddara ƙimar ƙima na wasu belun kunne na masana'anta na ANC a masana'anta. Tabbas, kwarewar sauraron wannan wayar kunne ta ANC a fili ba ta da kyau kamar na'urar kunne ta ANC tare da ma'anar daidaitawa ta gaskiya, saboda a cikin ainihin yanayi, hayaniyar waje dangane da shugabanci na belun kunne, yanayin zafi daban-daban da makamantansu na iya yin tasiri a kan. amsa tasha na kunnen kunne.
Tabbatar da Matlab
Rubuta lambar Matlab, ta yin amfani da tace mai daidaitawa na girman girman girman LMS, ana nuna sakamakon simintin a cikin Hoto 5. A cikin kewayon 0 zuwa 2 kHz, ana amfani da mai gabatarwa ANC don kawar da amo na Gaussian, kuma attenuation amo shine 30 dB + a matsakaita. FXLMS a cikin ɗakin karatu na Matlab ƙayyadaddun mataki ne, kuma tasirin ya fi muni.
Tambaya&A
a. Me yasa ANC kawai don ƙaramar amo a ƙasa da 2 kHz?
A gefe guda, rufin sauti na zahiri na belun kunne (raguwar amo mai wucewa) na iya toshe amo mai girma yadda ya kamata, kuma ba lallai ba ne a yi amfani da ANC don rage hayaniyar mitoci. A gefe guda kuma, ƙaramar ƙarar ƙararrawa tana da tsayi mai tsayi kuma tana iya jure wa wani ɗan lokaci jinkiri, yayin da ƙarar ƙarar ƙararrawa tana da ɗan gajeren zango kuma tana kula da karkatar lokaci, don haka ANC tana kawar da hayaniya mai girma.
b. Lokacin da jinkirin lantarki ya fi girma fiye da jinkiri na farko, ta yaya za a iya rage yawan aikin algorithm?
P(z) jinkiri karami ne, jinkirin S(z) babba ne, kamar P(z)=z-1, S(z)=z-2, kawai lokacin da W(z)=z zai iya biyan bukatu, ba - sanadi, ba za a iya isa ba.
c. Menene bambanci tsakanin Feedforward ANC, kunkuntar-band feedforward ANC, da ra'ayin ANC?
Tsarin Feedforwad yana da ref mic da kuskuren mic wanda ke tattara hayaniyar waje da sauran sigina na ciki, bi da bi. Tsarin martani yana da mic kuskure guda ɗaya kawai, kuma siginar tunani yana haifar da kuskuren mic da fitarwa mai daidaitawa.
Mai ba da labari mai faɗi shine tsarin da aka kwatanta a sama. A cikin ƙunƙuntaccen tsari, tushen amo yana haifar da janareta na siginar sigina, kuma janareta na siginar yana haifar da siginar tunani don tace mai daidaitawa. Ya dace kawai don kawar da hayaniyar lokaci-lokaci.
Feedback ANC yana amfani da mic na kuskure don dawo da siginar da aka tattara ta ref mic a cikin tsarin ciyarwa saboda kawai yana da mic kuskure. Hanyar ba ta gamsar da ƙaƙƙarfan dalili ba, don haka kawai abubuwan da za a iya tsinkaya amo, watau ƙarar hayaniyar lokaci-lokaci, an kawar da su. Ya kamata a lura cewa idan mai gabatarwa bai gamsar da ƙaƙƙarfan dalili ba, watau jinkirin lantarki ya fi tsayin jinkirin sauti na tashar tashar, zai iya kawar da ƙarar ƙarar lokaci-lokaci kawai.
Hakanan akwai tsarin ANC na Hybrid wanda ya haɗa da tsarin gabatarwa da tsarin amsawa. Babban fa'idar ita ce, zaku iya adana tsari na tace mai daidaitawa.
