Hello Habr.
A cikin 'yan shekarun nan, an tattauna gabatarwar DAB + dijital rediyo a Rasha, Ukraine da Belarus. Kuma idan har yanzu tsarin bai ci gaba ba a Rasha, to a cikin Ukraine da Belarus da alama sun riga sun canza zuwa gwajin watsa shirye-shirye.
Ta yaya yake aiki, menene fa'ida da rashin amfani, kuma shin ma ya zama dole? Cikakken bayani a ƙarƙashin yanke.
Fasaha
Tunanin rediyo na dijital ya fara fitowa a ƙarshen 80s, lokacin da ya bayyana cewa babu isassun “wurare” a cikin rukunin FM na yau da kullun ga kowa da kowa - a cikin manyan biranen, bakan kyauta a cikin kewayon 88-108 MHz ya kasance. gajiye. Dangane da wannan, an dauki DAB a matsayin madadin mai kyau - ma'aunin dijital ne wanda, saboda ingantaccen coding, ana iya sanya ƙarin tashoshi. Sigar farko ta DAB ta yi amfani da codec na MP2, sigar ta biyu (DAB+) ta yi amfani da sabuwar HE-AAC. Ma'aunin da kansa ya tsufa sosai ta tsarin zamani - an ƙaddamar da tashar DAB ta farko a cikin 1995, kuma tashar DAB + a cikin 2007. Bugu da ƙari, "shekarun" na ma'auni a cikin wannan yanayin ya fi girma fiye da ragi - yanzu babu matsala siyan mai karɓar radiyo don kowane dandano da kasafin kuɗi.
Akwai 'yan bambance-bambance tsakanin DAB da FM na yau da kullun. Kuma batu ba ma cewa ɗaya shine "lambobi", ɗayan kuma "analog". Ka'idar canja wurin abun ciki ta bambanta. A cikin FM, kowace tasha tana watsa shirye-shiryen kanta, yayin da a cikin DAB+, ana haɗa dukkan tashoshin zuwa "multiplex", kowannensu yana iya samun tashoshi 16. Ana ba da tashoshin mitoci daban-daban, ta yadda ƙasashe daban-daban za su iya zaɓar waɗanda ba su da sauran ayyuka.
Daga ra'ayi na kasuwanci, wannan bambance-bambance yana haifar da rikice-rikice tsakanin masu watsa shirye-shirye game da yadda ake watsawa a cikin multiplex. A baya, masu watsa shirye-shiryen da kansu sun sami lasisi don mita, sun sayi eriya da mai watsawa, yanzu za a ba da lasisi ga ma'aikacin multiplex, kuma ya riga ya ba da hayar tashoshi ga gidajen rediyo. Yana da wuya a ce ko ya fi kyau ko mafi muni, ya fi dacewa ga wani ya sami komai na kansa, ga wanda ya fi dacewa don haya.
Af, game da wannan, DAB yana da girma da ƙiba ga mai sauraro - Farashin haya na multiplex ya dogara da bitrate. Kuma idan kun zaɓi tsakanin 192 da 64kbps ... Ina tsammanin kowa ya fahimci abin da za a zaɓa. Idan yana da wahalar watsawa tare da ƙarancin inganci a FM, to a cikin DAB ana ƙarfafa shi ta hanyar tattalin arziki (a bayyane yake cewa wannan ba laifin masu haɓakawa bane, amma duk da haka). Farashin Rasha, ba shakka, har yanzu ba a sani ba, amma alal misali, zaku iya ganin farashin Ingilishi .
Daga mahangar fasaha, DAB+ multiplex sigina ce mai faɗi tare da faɗin bakan na kusan 1.5 MHz, wanda ke bayyane tare da mai karɓar RTL-SDR.
Ana iya samun ƙarin bayani a cikin PDF .
Matsayin gasa
Gabaɗaya, ba su da yawa. Ana amfani da DAB+ a Turai, ma'auni ya shahara a Amurka , a Indiya an gudanar da gwaje-gwaje tare da ma'auni amma yadda suka ƙare yana da wuya a ce.
Katin ya ɗan tsufa (An kuma gwada DRM a Rasha, amma an watsar da shi), amma ana iya fahimtar ra'ayin gaba ɗaya:
(tushe )
Ba kamar DAB ba, masu kirkiro na HD Radio misali sun ɗauki hanya daban-daban ta hanyar sanya siginar dijital kai tsaye kusa da siginar analog, ƙyale masu watsa shirye-shirye su yi amfani da nasu eriya da masts.
Duk da haka, wannan ba ya warware matsalar da ta fara shi duka - matsalar rashin kujerun kyauta a cikin bakan. Haka ne, kuma kawai geographically (kuma mai yiwuwa a siyasance), a cikin tsoffin ƙasashen CIS, ɗaukar ka'idodin Turai ya fi ma'ana fiye da yadda ake amfani da ma'aunin Amurka - zaɓin kayan Turai har yanzu ya fi girma kuma yana da sauƙin siyan masu karɓa. . A cikin 2011 akwai sauran ambaton , amma komai ya mutu (kuma alhamdulillahi, saboda nata tsarin dijital bai dace da komai ba, wannan shine mafi munin abin da za a iya ƙirƙira ga masu sauraron rediyo).
Gwaji
Daga karshe, mu ci gaba zuwa bangaren aiki, watau. don gwadawa. DAB ba ya aiki a Rasha tukuna, don haka za mu yi amfani da rikodin SDR daga yawancin Dutch. Wadanda suke so daga wasu kasashe kuma za su iya shiga su aiko mani da bayanai a cikin tsarin IQ, zan sarrafa su kuma in yi tebur mai pivot.
Ta yaya za ku saurari DAB? Domin misali na dijital, sannan za'a iya canza shi ta amfani da kwamfuta da mai karɓar rtl-sdr. Akwai shirye-shirye guda biyu - и , duka biyu na iya aiki tare da rtl-sdr.
yayi kama da takarda na ɗalibi, kuma marubucin a fili bai damu da ƙira ba - fonts ba su dace da sarrafawa ba, tagogi ba sa girma. Amma a gare mu, abu mafi mahimmanci shi ne cewa yana ba ku damar karantawa da rubuta fayilolin IQ.
har yanzu yana cikin beta, amma yana aiki mafi kyau kuma yana yanke mafi kyau. Hakanan yana yiwuwa a fitar da ƙarin ƙarin bayanan gyara kuskure masu yawa:
Amma welle.io bai san yadda ake aiki da fayilolin iq ba, don haka za mu yi amfani da Qt-dab.
Don gwaji, na loda fayilolin 3 zuwa cloud.mail.ru, kowannensu ya ƙunshi rikodin DAB multiplex na minti daya, girman fayil ɗin yana da kusan 500MB (wannan shine girman rikodin IQ na SDR tare da bandwidth na 2.4MHz). Kuna iya buɗe fayilolin a cikin Qt-dab, hanyar zazzagewar wacce aka bayar a sama.
Fayil-1:DAB-8A.sdr- . Multiplex 8A yana aiki a mitar 195.136 MHz kuma ya ƙunshi tashoshi 16. Matsakaicin ƙimar duk tashoshi shine 64Kbps.
Fayil-2:DAB-11A.sdr- . Multiplex 11A a mitar 216.928 MHz. Ya ƙunshi tashoshi 6, tare da bitrates na 48, 48, 48, 48, 64 da 48KBps bi da bi.
Fayil-3DAB-11C.sdr . Multiplex 11C a mitar 220.352 MHz, kuma ya ƙunshi tashoshi 16. Matsakaicin farashin duk tashoshi bi da bi: 80, 80, 80, 80, 56, 96, 80, 64, 56, 48, 64, 64, 64, 96, 80 da 64Kbps.
Kamar yadda kake gani, babu matsala game da adadin tashoshi, amma babbar matsalar ita ce ƙarancin bitrate. Game da abun ciki da kansa, dandano ya bambanta kuma ba zan tattauna shi ba, waɗanda suke so za su iya sauke fayilolin kuma su saurare su da kansu. Ba duk nau'ikan nau'ikan da aka jera a cikin shigarwar ba ne, amma babban ra'ayi shine, ina fata, a sarari.
binciken
Idan muka yi magana game da al'amuran watsa shirye-shiryen dijital, to, kash, sun fi bakin ciki. Babban fa'idar DAB shine mafi kyawun amfani da bakan, wanda ke ba da damar ƙarin tashoshi a cikin iska. Dangane da wannan, DAB + yana da ma'ana kawai ga waɗannan biranen da babu sarari kyauta a FM. Ga Rasha, wannan mai yiwuwa ne kawai Moscow da St. Petersburg, a duk sauran biranen babu irin waɗannan matsalolin.
Dangane da ingancin sauti, DAB+ na iya samar da ƙima ta fasaha har zuwa 192Kbps, wanda zai ba ku kusan sautin HiFi. A aikace, kamar yadda muke gani a sama, masu watsa shirye-shirye suna adana kuɗi kuma ba sa wuce mashaya ko da a 100Kbps. Daga cikin nau'ikan nau'ikan nau'ikan guda uku, tashar (!) ɗaya ce kawai aka sami tana watsa shirye-shiryen a 96Kbps (kuma ba zan iya kiran kiɗan watsa shirye-shiryen daga 48kbps wani abu ba face sabo - ya kamata a hana irin waɗannan masu watsa shirye-shiryen lasisin su;). Don haka, kash, muna iya faɗi da tabbacin 99% cewa lokacin canzawa daga FM zuwa DAB, ingancin sauti zai kasance. muni fiye da yadda yake. Tabbas, halin da ake ciki na iya zama mafi kyau a wasu ƙasashe, amma alal misali, bita na Turanci akan youtube tare da lakabi mai mahimmanci. . A fasaha, DAB yana da kyau kuma babu gunaguni game da shi, amma a fannin tattalin arziki, "wadanda suka ci nasara da mugunta."
Komawa zuwa Rasha, yana da kyau a damu don fara watsa shirye-shirye a cikin DAB kwata-kwata? Daga ra'ayi na kasa da kasa daraja, mai yiwuwa a, don kada a yi kama da baya a duniya ta uku kasa a idanun makwabta, da kuma a matsayin kari, ta yadda motoci da rediyo da aka saya a Turai iya cikakken samun duk tashoshi. Amma daga ra'ayi na masu sauraro da ingancin sauti, mai yiwuwa, masu amfani ba za su sami wani fa'ida ba ko dai a cikin ingancin sauti ko a cikin ingancin abun ciki.
Idan kuna tunanin makomar dogon lokaci, to tabbas a nan gaba rediyon zai zama na'ura mai haɗaɗɗiyar katin e-sim da kuma biyan kuɗi zuwa kiɗan Yandex Spotify ko Apple Music akan siye. Gaba a bayyane yake a cikin ayyukan yawo da keɓaɓɓen abun ciki. Ta yaya wannan zai faru, za mu gani, lokaci zai nuna.
source: www.habr.com