Nyquist Theorem - lub theoretical lub hauv paus ntawm niaj hnub ntaub ntawv yees

Ob peb ua tau li ntawd, qhov uas tau pab txoj kev loj hlob ntawm kev sib txuas lus thiab cov ntaub ntawv yees, raws li cov Nyquist theorem. By thiab loj, no paub txog tau qhuas peb lub teb chaws tsis muaj tsawg tshaj li tus SP Poj vaj, los yog AS Popov. Nws yog tau hais tias Kotelnikov paub sab nraum Russia txawm ntau tshaj li nyob rau hauv lub Fatherland.

Qhov no muaj koob meej nws muaj nws kev tshab txhais. Nyquist theorem los ua tus theoretical lub hauv paus rau tag nrho cov niaj hnub cov khoom siv rau kev sib txuas lus. Nws yog raws li nyob rau hauv lub hauv paus ntsiab lus ntawm digitizing tej teeb liab los yog duab. Nws tsim lub tej yam kev mob rau lub xam ntawm multi-channel kev sib txuas lus ntawm ib lub teeb liab khub. Vim lub Nyquist theorem, koj yuav restore nrov thiab "ragged" teeb liab, tsim kev tiv thaiv ntawm. Cryptographic txheej txheem kuj yog lom zem ntau raws li nyob rau hauv no theorem. Tej zaum nws yuav nrhiav tau lwm yam tseem ceeb daim ntawv sau npe.

Tus neeg sau ntawm xws tseem ceeb rau txoj kev loj hlob ntawm cov xov tooj cua theoretical ua hauj lwm tau yug los nyob rau hauv 1908 nyob rau hauv Kazan. Nws txiv yog ib tug university xibfwb, ib tug naas ej engineer thiab mathematician Aleksandr Petrovich Kotelnikov, ces thaum nws los txog rau noob, cov kev kawm nyob rau hauv Victor Alexandrovich yog "nyob rau hauv cov ntshav". Tom qab kawm tiav rau xyoo los ntawm lub Moscow Zog koom haum, tus tub hluas mus kawm tiav tsev kawm ntawv. Ntawm no ces yog xav nyob rau hauv nws lub npe bandwidth link muaj peev xwm. Cias muab, nws mas yuav ua li cas muaj coob tus neeg los ntawm txhua sab yuav hais tib yam xov tooj hlau (tsis muaj prejudice rau kev sib nrig sib to taub thiab intelligibility).

Kwv yees txog nws twb, thiab txawm tias, raws li nws muab tawm, heev muaj tseeb. Piv txwv li, lub Nyquist nyob rau hauv 1928 pom tias hais tias yog lub luag hauj lwm mus los ntawm cov kis lub teeb liab yog sib npaug zos rau ib nrab ntawm cov sij hawm ntawm lub siab tshaj plaws zaus, ces nws yuav tsum tau rov qab.

D = 1 / 2F,

qhov twg:

D - permissible lub sij hawm teeb liab disappears;

F-siab tshaj plaws zaus muaj nyob rau hauv lub teeb liab spectrum.

Nyquist tubntxhais assumed tias lub xov tooj lub teeb liab muaj ib tug ntau zaus ntawm 3 kHz, nws yog ua tau rau strobe ntawm ib zaus ntawm 6000 lub sij hawm ib ob uas tsis muaj tsis tseem ceeb.

Tej bold thiab intuitive xav cia niaj hnub historians ntawm science los ntawm Western lub teb chaws los hloov lub notion ntawm "Nyquist Theorem" tus sau lub npe. Nyquist theorem - hais tias yog lub npe ntawm Nyquist lub theorem nyob rau hauv ntau European thiab American cov phau ntawv. Txawm li cas los, nws yog ib tug tshaj plaws mus hais, txawm yog hais tias nws yog ib tug heev bold thiab paub tseeb hais tias los ntawm txoj kev xyaum, thiab lwm yam - los ua pov thawj nws. Theorem txawv los ntawm axioms los yog hypothesis, uas yog txhais yuav tsum tau ntawv pov thawj.

Ntawm no nws yog tsim nyog los them tribute rau peb Western cov phooj ywg. Xub Nyquist nyob rau hauv lub pov thawj ntawm "Nyquist Theorem" tsis muaj ib tug tsis sib haum.

Tsis muaj ib tug txaus siab txog qib uas paub ntawm kev kawm leb siab yog tsis yooj yim sua kom to taub yuav ua li cas exquisitely formulated Nyquist theorem. Lub pov thawj raws li ib tug approximation waveform uas qhia txog ib tug xov tooj Kotel'nikova (nws "plotting" los ntawm luv luv pulses).

Xws li ib tug theoretical lub hauv paus qhov tsawg kawg nkaus ntev ntawm tus mem tes teeb liab muab rau peb lub sijhawm siv mobile xov tooj hnub no, raws li zoo raws li digitized thiab raug duab ua, suab paj nruag thiab ntau lwm yam ntsiab lus.