Komkhawulokudonsa ukufinyelela kwenethiwekhi

Nge ekwandeni okwandile amanethiwekhi computer , igama elithi "i-bandwidth" laziwa wonke umuntu. Futhi uma isithakazelo ngaphambili kwaba luyingxenye theory, kodwa manje konkhe kwehlukile. Ukuqonda lokho yasisiza amazwi "lenethiwekhi" ikuvumela ukuthi ukhethe ezekhethelo wesevisi (lapha libhekisela inethiwekhi zendawo Internet), kanye nendlela elilungile ukuze usethe umsebenzi ngenethiwekhi.

Ngaphambi kokuthi lokumba theory, cabangela isimo esisebenzayo, okuyinto, ngeshwa, ngokuvamile ebhekene abasebenzisi Inthanethi abahlala yangaphambili amazwe eSoviet Union. Njengoba wazi, uma ukuxhuma abahlinzeki ukufinyelela kwenethiwekhi inkonzo in wemali yabo izinhlelo esebonisa isivinini nge isiqalo "phezulu." Ngokwesibonelo, "kuze kube-10 MB / s", "kuze kube-50 MB / s," njll

Empeleni, amandla ka isiteshi kanye ukubhuka ezixhunyiwe. Cabangela lesi simo ukuthi ngesikhathi esithile isikhathi inethiwekhi wesevisi ixhumanisa obhalisile. Njengomthetho, inikeza ngesivinini egcwele ukushaja. Ngo Ukuphishekela imigomo yezomnotho, umhlinzeki inkampani buyaqhubeka abasha ababhalisile. Ngenxa yalokho, kuba isimo zemvelo, lapho ngesikhathi esifanayo ukuqalisa uxhumano eziningi abasebenzisi inthanethi. Omunye tariff "50 MB", omunye, yesithathu ...

Umphumela onengqondo - izinga Iconsi zonke kushiwo ngezansi (khumbula isiqalo "phezulu"). Qala izingcingo ababhalisile abakhonondayo, izinkinga ezivamile nge zokuxhumana nokunye. Ngenxa yalokho, ukwesekwa okukhulunywa ukuthi bandwidth lilinganiselwe. Ngokuqinisekile, lokhu kuwubufakazi ajwayelekile kubasebenzisi abaningi. Mayelana kuyini nokuthi kungani ijubane uwa?

Ngo-1920, i-umcwaningi American Ralf Hartli electronics kanye physics Garri Nikvist, ekhuluma nezindaba lokudluliselwa Imininingwane e-Telegraph, zavela izici eziyinhloko inqubo ukudluliswa kwedatha. Enye yezindlela ezibaluleke kakhulu - ubuhlobo phakathi imvamisa yokudlulisela nesikhathi. Ngakho, Hartley washayelwa umthetho owawuthi isamba ngocansi idatha wakhona imvamisa ukudluliswa esetshenziswa futhi ukusebenza isikhathi. Ngo-1927 godu Nyqvist ecacisa ukuthi ngocansi lemali Inani kukhawulwe kabili imvamisa esetshenziswa (okusho ukudluliswa ngaphandle kokulahleka kwedatha per unit isikhathi). ngokufingqiwe imiphumela umsebenzi wabo kuphela, zavela imfundiso yokuziphendukela ngo-1940, Shannon idatha kanye umqondo welithi "uxhumano-bandwidth."

Ububanzi imvamisa esetshenziselwa ukuthutha kolwazi isiteshi ibizwa ngokuthi "i-bandwidth". Kusukela theorem Shannon kubonisa ukuthi ekufezeni ngesivinini esiphezulu kungenzeka ngokwandisa amandla isignali, i-bandwidth, yehlisa kakhulu umsindo womhlabathi ezikhohlisayo. isivinini kukhuphuke ngo isignali ukushintshashintsha kwezwi kunzima, ngoba lapho ishayela okwandisa kunciphisa inani eliphelele per unit isikhathi, futhi ngesikhathi compaction ngokunciphisa nesikhathi osenyameni olulodwa kwandisa umthamo ukulahlekelwa e umqhubi. Ngokuvamile, ububanzi ishayela ibalwa ifomula ucabangela imvamisa ekhethiwe.

Kufanele kuqashelwe ukuthi amandla isiteshi kuhlanganisa hhayi kuphela isignali oyifunayo kodwa futhi umsindo. Lokhu kungaba ukuphazamiseka kagesi, property umqhubi, inqubo reflection Gauss nokunye. Owamukelayo uthola ukugeleza egcwele amasignali futhi ukuhlunga ingxenye oyifunayo.

Uma sibuyela esibonelweni: lapho inombolo enkulu ababhalisile safinyelela ngokushesha umkhawulo we Imininingwane ekusakazeni idatha ku imvamisa ukudluliswa esetshenziswa umhlinzeki (line optical, isixhumanisi umsakazo, ithusi wire). Ukuxazulula lenkinga, kwandisa amandla isignali ukushintsha imvamisa ukuwudlulisa imvelo (ebizayo njengoba kudinga sesimanje imishini), noma ibeke umkhawulo ukugeleza idatha kusuka isikhokhelo ngamunye owenziwa.