Hello Habr.
M'zaka zaposachedwa, kukhazikitsidwa kwa digito yawayilesi ya DAB + yakambidwa ku Russia, Ukraine ndi Belarus. Ndipo ngati ku Russia ndondomekoyi siidapitirire, ndiye ku Ukraine ndi Belarus zikuwoneka kuti asintha kale kuyesa kuyesa.
Zimagwira ntchito bwanji, zabwino ndi zoyipa zake ndi ziti, ndipo ndizofunika konse? Tsatanetsatane pansi pa odulidwa.
umisiri
Lingaliro la wailesi ya digito linayamba kuonekera chakumapeto kwa zaka za m'ma 80, pamene zinaonekeratu kuti panalibenso "malo" okwanira mu gulu lokhazikika la FM kwa aliyense - m'mizinda ikuluikulu mawonekedwe aulere mu 88-108 MHz anali. watopa. Pachifukwa ichi, DAB inkaonedwa kuti ndi njira ina yabwino - ndi mulingo wa digito momwe, chifukwa cholembera bwino, masiteshoni ambiri amatha kukhalamo. Mtundu woyamba wa DAB unagwiritsa ntchito MP2 codec, mtundu wachiwiri (DAB+) unagwiritsa ntchito HE-AAC yatsopano. Muyezo womwewo ndi wakale kwambiri malinga ndi miyezo yamakono - siteshoni yoyamba ya DAB yomwe idakhazikitsidwa mu 1995, ndi siteshoni ya DAB + mu 2007. Komanso, "m'badwo" wa muyezo pankhaniyi ndi wowonjezera kuposa kuchotsera - tsopano palibe vuto kugula wolandila wailesi pazokonda zilizonse ndi bajeti.
Pali kusiyana kochepa pakati pa DAB ndi ma FM wamba. Ndipo mfundo siili ngakhale kuti imodzi ndi "digito" ndipo ina ndi "analogi". Mfundo ya kusamutsa okhutira palokha ndi yosiyana. Mu FM, wailesi iliyonse imawulutsa paokha, ndipo mu DAB+, masiteshoni onse amaphatikizidwa kukhala "multiplex", iliyonse yomwe imatha kukhala ndi masiteshoni 16. Makanema osiyanasiyana amaperekedwa kuti mayiko osiyanasiyana asankhe omwe alibe ntchito zina.
Kuchokera pamalingaliro abizinesi, kusiyana uku kumayambitsa mikangano yambiri pakati pa owulutsa za momwe amawulutsira mu multiplex. M'mbuyomu, owulutsa okha adalandira layisensi ya frequency, adagula antenna ndi transmitter, tsopano chilolezocho chidzaperekedwa kwa wogwiritsa ntchito multiplex, ndipo adzabwereketsa mawayilesi kumawayilesi. Ndizovuta kunena ngati zili bwino kapena zoyipitsitsa, kwa ena ndizosavuta kukhala ndi chilichonse chawochawo, kwa ena ndizosavuta kubwereka.
Mwa njira, pankhaniyi, DAB ili ndi vuto lalikulu komanso lolimba mtima kwa omvera - multiplex mtengo wobwereketsa umadalira bitrate. Ndipo ngati mungasankhe pakati pa 192 ndi 64kbps... Ndikuganiza kuti aliyense amvetsetsa zomwe zidzasankhidwa. Ngati mu FM ndizovuta kufalitsa ndi khalidwe losauka, ndiye kuti mu DAB izi zimalimbikitsidwa ngakhale pazachuma (zikuwonekeratu kuti uku si kulakwa kwa omwe akupanga muyezo, komabe). Mitengo ya ku Russia, ndithudi, sichidziwikabe, koma mitengo ya Chingerezi, mwachitsanzo, ingapezeke .
Kuchokera pamalingaliro aukadaulo, DAB + multiplex ndi chizindikiro cha Broadband chokhala ndi sipekitiramu yayikulu pafupifupi 1.5 MHz, yomwe imawoneka bwino pogwiritsa ntchito cholandila cha RTL-SDR.
Kufotokozera mwatsatanetsatane mu PDF kungapezeke .
Miyezo yopikisana
Ambiri, palibe ambiri a iwo. DAB + imagwiritsidwa ntchito ku Europe, muyezo ndiwodziwika ku USA , ku India iwo anayesa muyezo , koma nβzovuta kunena mmene anathera.
Khadi ndi lachikale pang'ono (DRM idayesedwanso ku Russia, koma idasiyidwa), koma lingaliro lonse limatha kumveka:
(gwero )
Mosiyana ndi DAB, omwe amapanga HD Radio muyezo adatengera njira yosiyana - chizindikiro cha digito chimayikidwa molunjika pafupi ndi chizindikiro cha analogi, kulola otsatsa kuti agwiritse ntchito ma antennas awo ndi masts.
Komabe, izi sizithetsa vuto lomwe lidayambitsa zonse - vuto la kusowa kwa mipata yaulere pamawonekedwe. Ndipo mwachilengedwe (ndipo mwina ndale), m'maiko omwe kale anali CIS, kukhazikitsidwa kwa muyezo waku Europe kumawoneka koyenera kuposa kugwiritsa ntchito muyezo waku America - pali kusankha kwakukulu kwa katundu waku Europe ndipo ndikosavuta kugula olandila. Zinali zotchulidwabe mu 2011 , koma chirichonse chinafa (ndikuthokoza Mulungu, chifukwa muyezo wake wa digito, womwe sugwirizana ndi chirichonse, ndi chinthu choipa kwambiri chomwe chingapangidwe kwa omvera wailesi).
Kuyesa
Tiyeni potsiriza tipite ku gawo lothandizira, i.e. ku kuyezetsa. DAB sikugwirabe ntchito ku Russia pano, kotero tidzagwiritsa ntchito zojambulira za SDR kuchokera ku Dutch multiplex. Ochokera kumayiko ena amathanso kujowina ndikunditumizira ma rekodi mu mtundu wa IQ, ndidzawakonza ndikupanga tebulo lachidule.
Kodi mungamvetsere bwanji DAB? Chifukwa muyezo ndi digito, mutha kuyilemba pogwiritsa ntchito kompyuta ndi cholandila cha rtl-sdr. Pali mapulogalamu awiri - ΠΈ , onse amatha kugwira ntchito ndi rtl-sdr.
zikuwoneka ngati ntchito ya maphunziro a wophunzira, ndipo wolembayo sanavutike ndi mapangidwewo - mafonti sakugwirizana ndi zowongolera, mazenera samakula. Koma chofunikira kwambiri kwa ife ndikuti chimakulolani kuti muwerenge ndi kulemba mafayilo a IQ.
Ikadali mu beta, koma imagwira ntchito bwino kwambiri ndikuzindikira bwino. Ndikothekanso kutulutsa zambiri zowonjezera zowonjezera:
Koma welle.io sadziwa momwe angagwiritsire ntchito mafayilo a iq, kotero tidzagwiritsa ntchito Qt-dab.
Poyesa, ndinakweza mafayilo atatu ku cloud.mail.ru, iliyonse ili ndi kujambula kwa mphindi yayitali ya DAB multiplex, kukula kwa fayilo ndi pafupifupi 3 MB (uku ndi kukula kwa zojambula za IQ za SDR ndi 500 MHz bandwidth). Mutha kutsegula mafayilo mu Qt-dab, ulalo wotsitsa womwe waperekedwa pamwambapa.
Fayilo-1Chithunzi: DAB-8A.sdr . Multiplex 8A imagwira ntchito pafupipafupi 195.136 MHz ndipo imakhala ndi masiteshoni 16. Bitrate ya masiteshoni onse ndi 64Kbps.
Fayilo-2Chithunzi: DAB-11A.sdr . Multiplex 11A pafupipafupi 216.928 MHz. Ili ndi masiteshoni 6, okhala ndi ma bitrate a 48, 48, 48, 48, 64 ndi 48KBps motsatana.
Fayilo-3Chithunzi: DAB-11C.sdr . Multiplex 11C pafupipafupi 220.352 MHz ilinso ndi masiteshoni 16. Ma bitrate a masiteshoni onse ndi motsatana: 80, 80, 80, 80, 56, 96, 80, 64, 56, 48, 64, 64, 64, 96, 80 ndi 64Kbps.
Monga mukuonera, palibe mavuto ndi chiwerengero cha masiteshoni, koma vuto lalikulu ndi otsika bitrate. Ponena za zomwe zili pawokha, zokonda zimasiyana ndipo sindikambirana; omwe akufuna akhoza kutsitsa mafayilo ndikumvera okha. Sikuti ma multiplex onse alembedwa m'malembawo, koma ndikuyembekeza kuti lingaliro lonse liri lomveka.
anapezazo
Ngati tilankhula za chiyembekezo chowulutsa pawailesi ya digito, zili, tsoka, zachisoni kwambiri. Ubwino waukulu wa DAB ndikugwiritsa ntchito bwino ma sipekitiramu, zomwe zimalola kuti masiteshoni ambiri aziyikiridwa pamlengalenga. Pachifukwa ichi, DAB + imangokhala yomveka kwa mizinda yomwe mulibenso malo aulere mu FM. Kwa Russia, izi mwina ndi Moscow ndi St. Petersburg zokha; m'mizinda ina yonse mulibe mavuto otere.
Ponena za kamvekedwe ka mawu, mwaukadaulo, DAB+ imatha kupereka ma bitrate mpaka 192Kbps, yomwe ipereka pafupifupi mawu a HiFi. Zochita, monga tikuwonera pamwambapa, otsatsa amasunga ndalama ndipo samawoloka ngakhale 100Kbit / s bar. Mwa ma multiplex atatu, panali imodzi yokha (!) siteshoni yowulutsa pa 96Kbps (ndipo sindingatchule nyimbo zowulutsa pa 48kbps china chilichonse kupatula mwano - owulutsa otere ayenera kulandidwa laisensi yawo;). Chifukwa chake, tsoka, titha kunena ndi chidaliro cha 99% kuti mukasintha kuchokera ku FM kupita ku DAB, mtundu wamawu udzakhala zoipa kuposa izo. Zachidziwikire, mwina m'maiko ena zinthu zili bwino, koma mwachitsanzo, nayi ndemanga yachingerezi pa YouTube yokhala ndi mutu womveka bwino. . Mwaukadaulo, DAB ndiyabwino ndipo palibe zodandaula nazo, koma mwachuma, "ndalama zidapambana zoyipa."
Kubwerera ku Russia, kodi ndikoyenera kuvutitsidwa ndikuyamba kuwulutsa ku DAB? Kuchokera pakuwona kutchuka kwa mayiko, mwina inde, kuti musawoneke ngati dziko lachitatu lakumbuyo m'maso mwa oyandikana nawo, komanso ngati bonasi, kuti magalimoto ndi mawailesi ogulidwa ku Ulaya athe kulandira bwino masiteshoni onse. Koma pakuwona kwa omvera ndi mtundu wamawu, mwina, ogwiritsa ntchito sangalandire zabwino zilizonse kaya mumtundu wamawu kapena mtundu wa zomwe zili.
Ngati tiganizira za chiyembekezo cha nthawi yayitali, ndiye kuti mwina m'tsogolomu wolandila wailesi adzakhala chipangizo chokhala ndi e-sim khadi yophatikizika ndikulembetsa ku Yandex nyimbo Spotify kapena Apple Music mukagula. Tsogolo liri la ntchito zotsatsira komanso zokonda zanu. Kodi izi zichitika posachedwa bwanji, tiwona, nthawi itiuza.
Source: www.habr.com