Coding na audio bayanai

Duk wani tsari za a zahiri za a tuba a cikin digital form. Saboda haka, tsarinsa na audio bayanai via kwakwalwa ne da za'ayi kamar haka:

- iska vibrations rubuta m na'urorin.

- kashe hira cikin wani lantarki halin yanzu, cikinsa da mita (mawadãta) dabam daidai da;

- sakamakon halin yanzu da aka dauka samfur, Ina nufin akwai ta daukan samfur (wani lokacin ce cewa riko da binary tsarinsa audio bayanai).

A sakamakon analog lantarki masu juwuwa na asali kwarara cikin mafi alhẽri, mafi girma da mita na samfurori a Samfur da kuma coding zurfin.

A wasu kalmomin, tsarinsa na audio bayanai - shi ne mai saba aiwatar da mayar da yawa analog sigina cikin wani dijital, akayi nufi don ci gaba da aiki da ya dace da na'urar. Bari mu bincika matakai da hanyoyin da digitizing sauti.

Discretization na lokaci frame - shi ne dalilin digitizing. A cewar Kotel'nikova Theorem, da analogue sakonni, za a iya digitized da karanta wani mataki na ci gaba da jerin dabi'u na ta mawadãta. A mita na irin wannan karatu ya kamata a kalla sau biyu iyaka mita na babban alama. Idan dole, digitizing analogue "source code" zuwa aiki mita na 0-20 kHz Samfur kamata a da za'ayi ba kasa da dubu 40. Times ta biyu (40 kHz). Samfur yana nufin yawan ma'aunai da biyu analog sigina tushen (daukan samfur, da daukan samfur mita). Tare da kara samfurin ƙaruwa ba kawai da ingancin amma kuma ƙara da sakamakon data rafi.

Har ila yau, audio bayanai coding iya yi a sauran hanyoyi. Kamar yadda, misali, ta hanyar digitizing da nonuniform quantizer, wani lokacin kira logarithmic. Lokacin amfani da dukan mawadãta kewayon yanaye kasu kashi sassan da high da kuma low dabi'u. Bugu da ari tsarinsa audio bayanai na faruwa da ake ji yawa quantization matakai a yankunan da kananan mawadãta darajar (da kuma mataimakin versa). Lura, duk da haka, cewa jimlar yawan matakan rage guda kamar yadda a cikin uniform quantization Hanyar (PCM).

An gaba ɗaya daban-daban m ake aiwatar a madadin tsarinsa Hanyar. Shi ne ake kira "bambanci Pulse Code daidaitowa» (DPCM). Tare da irin wannan hanya ba hõre quantization na mawadãta daga kai tsaye siginar da ta zumunta darajar. A sakamakon yiwu a cimma akan rage ƙarar shagaltar da ta data, tun da dabarar da aka sarrafa m Hasashen na asali siginar samfurori.

A coding da kuma aiki audio bayanai da aka bayyana a cikin wannan takarda bukatar yin hira "analog-to-dijital". Wannan tsari aka yi amfani da wani Dogarin (analog-to-dijital Converter). Tare da wannan aiki, kowane na'urar fuskantar kullum kwamfuta mai sanye take da wani sauti katin (a cikin wannan harka akwai wani kuma baya da tsari - karbar analog sigina daga dijital rafi).

Dogarin ayyuka ne kamar haka:

- iyaka mita bandwidth. Amfani da tacewa, da alama aka gyara an yanke, da mita daga wanda - fiye da rabin da daukan samfur mita (dalilin da aka bayyana a baya).

- Selection na mawadãta dabi'u a yau da kullum jinkiri. A sakamakon analog siginar da aka wakilta wani jerin guda ragowa da sãɓãwar launukansa tsanani (discretization).

- Sauyawa yawa samu ragowa da mafi kusa dabi'u daga wani ajali sa (quantization).

- Maida kowane quantized darajar da matukar yawan quantization matakan (kowane darajar - ta serial number). Wannan shi ne na karshe mataki na digitization.