Veza ukuthi yimaphi amagama angeke adlulise; ukuzwa imizwa ehlukahlukene ehlangene esiphepho semizwa; ukugqashuka emhlabeni, isibhakabhaka kanye ne-Universe uqobo, ahambe ohambweni lapho kungekho mabalazwe, kungekho migwaqo, kungekho zimpawu; sungula, xoxa futhi uzizwele yonke indaba ezohlala iyingqayizivele futhi ingenakulinganiswa. Konke lokhu kungenziwa ngomculo - ubuciko obukhona izinkulungwane eziningi zeminyaka futhi obujabulisa izindlebe nezinhliziyo zethu.
Kodwa-ke, umculo, noma kunalokho imisebenzi yomculo, ayikwazi ukukhonza kuphela ukuzijabulisa kobuhle, kodwa futhi nokudluliselwa kolwazi olufakwe kuyo, oluhloselwe idivayisi ethile futhi engabonakali kumlaleli. Namuhla sizojwayelana nesifundo esingavamile kakhulu lapho abafundi abaphothule e-ETH Zurich bekwazi, bengaboni indlebe yomuntu, ukwethula idatha ethile emisebenzini yomculo, ngenxa yokuthi umculo ngokwawo uba isiteshi sokudlulisa idatha. Babusebenzise kanjani ngempela ubuchwepheshe babo, ingabe imiculo enedatha eshumekiwe nangenayo ihluke kakhulu, futhi ukuhlola okungokoqobo kwabonisani? Sifunda ngalokhu embikweni wabacwaningi. Hamba.
Isisekelo socwaningo
Abacwaningi babiza ubuchwepheshe babo be-acoustic data transmission technology. Lapho isikhulumi sidlala ingoma eguquliwe, umuntu ukubheka njengento evamile, kodwa, isibonelo, i-smartphone ingafunda ulwazi olufakwe ikhodi phakathi kwemigqa, noma kunalokho phakathi kwamanothi, ngomqondo ongokomfanekiso. Ososayensi (iqiniso lokuthi laba bafana basengabafundi abaneziqu alibavimbeli ekubeni ososayensi) babiza isivinini nokuthembeka kokudluliselwa ngenkathi kugcinwa izinga lala mapharamitha, kungakhathaliseki ukuthi ifayela elilalelwayo elikhethiwe, njengesici esibaluleke kakhulu ekusetshenzisweni le nqubo yokudlulisa idatha. I-Psychoacoustics, efunda izici ezingokwengqondo nezokuphila zombono womuntu wemisindo, isiza ukubhekana nalo msebenzi.
Umnyombo wokudluliswa kwedatha ye-acoustic ungabizwa nge-OFDM (i-orthogonal frequency division multiplexing), okuthe, kanye nokujwayela ama-subcarriers emculweni womthombo ngokuhamba kwesikhathi, kwenze kwaba nokwenzeka ukusebenzisa kakhulu i-spectrum yefrikhwensi yokudlulisa ukuze kudluliselwe ulwazi. Ngenxa yalokhu, kwakungenzeka ukufeza isivinini sokudlulisela esingu-412 bps ngebanga elingafika kumamitha angu-24 (izinga lephutha <10%). Ukuhlola okungokoqobo okuhilela amavolontiya angu-40 kwaqinisekisa iqiniso lokuthi cishe akunakwenzeka ukuzwa umehluko phakathi komculo wokuqala kanye nalowo okwashunyekwa kuwo ukwaziswa.
Lobu buchwepheshe bungasetshenziswa kuphi ekusebenzeni? Abacwaningi banempendulo yabo: cishe wonke ama-smartphones esimanje, ama-laptops nezinye izisetshenziswa eziphathwayo zifakwe imakrofoni, futhi izindawo eziningi zomphakathi (amathilomu, izindawo zokudlela, izikhungo zokuthenga, njll.) zinezipikha ezinomculo wangemuva. Lo mculo wangemuva ungafaka, isibonelo, idatha yokuxhuma kunethiwekhi ye-Wi-Fi ngaphandle kwesidingo sezenzo ezengeziwe.
Izici ezijwayelekile zokudluliswa kwedatha ye-acoustic sezicacile kithi; manje ake siqhubekele esifundweni esinemininingwane yokwakheka kwalolu hlelo.
Incazelo Yesistimu
Ukwethulwa kwedatha emculweni kwenzeka ngenxa yokufihla imvamisa. Ezikhaleni zesikhathi, imvamisa yokufihla iyabonakala futhi abathwali abangaphansi be-OFDM eduze kwalezi zakhi zokufihla bagcwaliswa ngedatha.
Isithombe #1: Ukuguqula ifayela lokuqala libe isignali eyinhlanganisela (umculo + idatha) edluliselwa ngezipikha.
Okokuqala, isignali yomsindo yoqobo ihlukaniswa ngamasegimenti alandelayo ukuze ahlaziywe. Ingxenye ngayinye enjalo (Hi) ka-L = 8820 amasampula, alingana no-200 ms, iphindaphindwa ifasitela* ukunciphisa imiphumela yemingcele.
Iwindi* kuwumsebenzi wokulinganisa osetshenziselwa ukulawula imiphumela ngenxa yama-sidelobes ekulinganisweni kwe-spectral.
Okulandelayo, amafrikhwensi avelele wesignali yoqobo atholwe kububanzi obusuka ku-500 Hz ukuya ku-9.8 kHz, okwenze kwaba nokwenzeka ukuthola amafrikhwensi okufihla i-fM,l kule ngxenye. Ngaphezu kwalokho, idatha idluliselwe ebangeni elincane ukusuka ku-9.8 ukuya ku-10 kHz ukuze kutholwe indawo yezinkampani zenethiwekhi kumamukeli. Umkhawulo ongaphezulu webanga lemvamisa elisetshenzisiwe wawusethelwe ku-10 kHz ngenxa yokuzwela okuphansi kwamakrofoni e-smartphone kumafrikhwensi aphezulu.
Amafrikhwensi okufihla anqunyelwe ingxenye ngayinye ehlaziywe ngayodwa. Kusetshenziswa indlela ye-HPS (Harmonic Product Spectrum), amafrikhwensi amathathu avelele ahlonzwa futhi azungezwa kumanothi aseduze esikalini se-harmonic chromatic. Lena yindlela amanothi ayinhloko u-fF,i = 1β¦3 atholwe ngayo, elele phakathi kokhiye u-C0 (16.35 Hz) no-B0 (30.87 Hz). Ngokusekelwe eqinisweni lokuthi amanothi ayisisekelo aphansi kakhulu ukuthi angasetshenziselwa ukudluliswa kwedatha, ama-octave awo aphezulu angu-500kfF,i abalwe kububanzi obungu-9.8 Hz ... 2 kHz. Eziningi zalawa mafrikhwensi (fO,l1) aye agqama kakhulu ngenxa yesimo se-HPS.
Isithombe #2: Ama-octaves abaliwe okuthi FO,l1 wamanothi ayisisekelo nama-harmonics fH,l2 wethoni enamandla kakhulu.
Isethi ewumphumela yama-octave nama-harmonics asetshenziswa njengamafrikhwensi okufihla, lapho kwatholakala khona amafrikhwensi e-OFDM yenethiwekhi ye-fSC,k. Izithwali ezingaphansi ezimbili zifakwe ngezansi nangaphezulu kwefrikhwensi ngayinye yokufihla.
Okulandelayo, i-spectrum yengxenye yomsindo we-Hi yahlungwa kumafrikhwensi e-subcarrier fSC,k. Ngemva kwalokho, uphawu lwe-OFDM lwakhiwa ngokusekelwe kumabhithi olwazi ku-Bi, ngenxa yokuthi ingxenye eyinhlanganisela Ci yayingase idluliselwe ngesipika. Ubukhulu nezigaba zama-subcarriers kufanele kukhethwe ukuze umamukeli akwazi ukukhipha idatha edlulisiwe kuyilapho umlaleli engaboni izinguquko emculweni.
Isithombe esingu-3: ingxenye ye-spectrum kanye namafrikhwensi enkampani engaphansi yengxenye ye-Hi yomculo woqobo.
Uma isignali yomsindo enolwazi olufakwe kuyo idlalwa ngezipikha, imakrofoni yedivayisi eyamukelayo iyayirekhoda. Ukuze uthole izindawo zokuqala zezimpawu ezishumekiwe ze-OFDM, amarekhodi adinga kuqala ukuthi ahlungwe i-bandpass. Ngale ndlela, ububanzi befrikhwensi ephezulu bukhishwa, lapho kungekho khona izimpawu zokuphazanyiswa komculo phakathi kwama-subcarriers. Ungathola isiqalo sezimpawu ze-OFDM usebenzisa isiqalo somjikelezo.
Ngemva kokuthola ukuqala kwezimpawu ze-OFDM, umamukeli uthola ulwazi mayelana namanothi avelele kakhulu ngokuqoshwa kwesizinda semvamisa ephezulu. Ngaphezu kwalokho, i-OFDM imelana neze nemithombo yokuphazamiseka kwe-narrowband, njengoba ithinta kuphela ezinye zezinkampani ezingaphansi.
Izivivinyo ezingokoqobo
Isipikha se-KRK Rokit 8 sisebenze njengomthombo wezingoma ezishintshiwe, futhi i-smartphone ye-Nexus 5X idlale indima yokwamukela iqembu.
Isithombe #4: Umehluko phakathi kwe-OFDM yangempela neziqongo zokuhlobana zikalwa endlini ngo-5m phakathi kwesipikha nemakrofoni.
Amaphoyinti amaningi e-OFDM asebangeni elisuka ku-0 kuye ku-25 ms, ukuze ukwazi ukuthola isiqalo esivumelekile phakathi kwesiqalo esingumjikelezo esingu-66.6 ms. Abacwaningi baqaphela ukuthi umamukeli (kulokhu kuhlolwa, i-smartphone) ucabangela ukuthi izimpawu ze-OFDM zidlalwa ngezikhathi ezithile, okuthuthukisa ukutholwa kwazo.
Into yokuqala okufanele ihlolwe kube umphumela webanga kusilinganiso sephutha elincane (BER). Ukuze wenze lokhu, kwenziwa izivivinyo ezintathu ezinhlotsheni ezihlukene zamakamelo: umhubhe onokhaphethi, ihhovisi eline-linoleum phansi, nehholo elinendawo yokhuni.
Ingoma ethi βAnd The Cradle Will Rockβ kaVan Halen yakhethwa njengesihloko sokuhlolwa.
Ivolumu yomsindo yalungiswa ukuze izinga lomsindo likalwe yi-smartphone ebangeni elingu-2 m ukusuka kusipika libe ngu-63 dB.
Isithombe No. 5: Izinkomba ze-BER kuye ngokuthi ibanga phakathi kwesipika kanye nemakrofoni (umugqa oluhlaza okwesibhakabhaka - izethameli, oluhlaza - umhubhe, i-orange - ihhovisi).
Ephasishi, umsindo we-40 dB uthathwe yi-smartphone ebangeni elingafika kumamitha angama-24 ukusuka kusipika. Ekilasini ebangeni elingu-15 m umsindo wawungu-55 dB, futhi ehhovisi ebangeni elingamamitha angu-8 izinga lomsindo elibonwa yi-smartphone lifinyelele ku-57 dB.
Ngenxa yokuthi ihholo nehhovisi kuphendula kakhulu, izimpawu ze-OFDM sekwephuzile zedlula ubude besiqalo somjikelezo futhi andise i-BER.
I-Reverberation* - ukwehla kancane kancane kokuqina komsindo ngenxa yokubukeka kwayo okuningi.
Abacwaningi baphinde babonisa ukuguquguquka kwesistimu yabo ngokuyisebenzisa ezingomeni ezi-6 ezihlukene ezivela ezinhlotsheni ezintathu (ithebula elingezansi).
Ithebula No. 1: izingoma ezisetshenziswa ekuhlolweni.
Futhi, ngedatha yethebula, singabona isilinganiso sebhithi kanye nezilinganiso zamaphutha engoma ngayinye. Amanani edatha ahlukile ngenxa yokuthi i-BPSK ehlukile (i-phase shift keying) isebenza kangcono uma kusetshenziswa izinkampani zenethiwekhi ezifanayo. Futhi lokhu kungenzeka uma izingxenye eziseduze ziqukethe izinto ezifanayo zokufihla. Izingoma ezinomsindo eziqhubekayo zinikeza isisekelo esilungile sokufihla idatha ngenxa yokuthi amafrikhwensi okufihla atholakala kakhulu ebangeni elibanzi lefrikhwensi. Umculo osheshayo ungavala kancane kuphela izimpawu ze-OFDM ngenxa yobude obumisiwe bewindi lokuhlaziya.
Okulandelayo, abantu baqala ukuhlola uhlelo, okwakudingeka banqume ukuthi imuphi umculo owawungowokuqala nokuthi yimuphi owashintshwa ulwazi olushunyekiwe kulo. Ngale njongo, izingcaphuno zemizuzwana engu-12 zezingoma ezivela kuthebula No. 1 zafakwa kuwebhusayithi ekhethekile.
Esivivinyweni sokuqala (E1), umhlanganyeli ngamunye wanikwa isiqeshana esilungisiwe noma sangempela ukuze asilalele futhi kwadingeka anqume ukuthi ucezu olwangempela noma lulungisiwe yini. Ocwaningweni lwesibili (E2), ababambiqhaza bangalalela zombili izinguqulo izikhathi eziningi ngokuthanda kwabo, bese benquma ukuthi iyiphi eyangempela nokuthi iyiphi elungisiwe.
Ithebula No. 2: imiphumela yokuhlolwa kwe-E1 ne-E2.
Imiphumela yokuhlolwa kokuqala inezinkomba ezimbili: p(O|O) - iphesenti labahlanganyeli abamake kahle ingoma yoqobo kanye no-p(O|M) - iphesenti labahlanganyeli abamake inguqulo eguquliwe yomculo njengeyangempela.
Kuyathakazelisa ukuthi abanye ababambiqhaza, ngokusho kwabacwaningi, babheka imiculo ethile eguquliwe njengeyangempela kuneyasekuqaleni ngokwayo. Isilinganiso sakho kokubili ukuhlola siphakamisa ukuthi umlaleli ojwayelekile ngeke abone umehluko phakathi komculo ovamile kanye nalowo lapho idatha ishunyekwe khona.
Ngokwemvelo, ochwepheshe bomculo nabaculi bazokwazi ukubona izinto ezingalungile nezinto ezisolisayo ezingoma ezishintshiwe, kodwa lezi zakhi azibaluleki kangako kangangokuthi zingabangela ukungakhululeki.
Futhi manje nathi ngokwethu singabamba iqhaza ekuhlolweni. Ngezansi kunezinguqulo ezimbili zomculo ofanayo - owokuqala noshintshiwe. Uyawuzwa umehluko?
vs
Ukuze uthole ulwazi oluningiliziwe ngama-nuances ocwaningo, ngincoma ukubheka iqembu locwaningo.
Futhi ungadawuniloda ingobo yomlando ye-ZIP yamafayela alalelwayo amashuni asekuqaleni naguquliwe asetshenziswe ocwaningweni .
Epilogue
Kulo msebenzi, abafundi abaneziqu e-ETH Zurich bachaze uhlelo olumangalisayo lokudlulisa idatha ngaphakathi komculo. Ukwenza lokhu, basebenzise imaski yokuvama, okwenze kwaba nokwenzeka ukushumeka idatha emculweni odlalwa yisipika. Lo mculo ubonwa imakrofoni yedivayisi, ebona idatha efihliwe futhi iyisuse amakhodi, kuyilapho umlaleli ojwayelekile ngeke aze awubone umehluko. Ngokuzayo, abafana bahlela ukuthuthukisa uhlelo lwabo, bekhetha izindlela ezithuthuke kakhulu zokwethula idatha kumsindo.
Uma othile eza nento engavamile, futhi okubaluleke kakhulu, into esebenzayo, sihlala sijabule. Kodwa intokozo enkulu nakakhulu ukuthi lokhu kusungulwa kwasungulwa abantu abasha. Isayensi ayinayo imingcele yobudala. Futhi uma intsha ithola isayensi iyisicefe, kusho ukuthi yethulwa ngendlela engafanele. Phela, njengoba sazi, isayensi iyizwe elimangalisayo elingayeki ukumangala.
NgoLwesihlanu ekuseni:
Njengoba sikhuluma ngomculo, noma kunalokho umculo we-rock, nali uhambo oluhle phakathi kwe-rock expanses.
Queen, "Radio Ga Ga" (1984).
Siyabonga ngokufunda, hlalani nelukuluku, futhi nibe nempelasonto enhle bafana! π
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Source: www.habr.com