QAM, Quadrature Amplitude Modulation
Jun 17, 2017
Quadrature Amplitude Modulation los yog QAM yog ib qho ntawm cov qauv siv dav dav uas yog siv rau kev hloov cov ntaub ntawv qhia rau cov cab kuj siv rau xov tooj cua sib txuas lus. Nws yog dav siv vim nws muaj zoo dua lwm cov ntaub ntawv ntawm cov ntaub ntawv xws li PSK, txawm tias muaj ntau hom kev qhia ntawv ua haujlwm ua ke nrog txhua lwm yam.
Quadrature Amplitude Modulation, QAM yog ib lub teeb liab uas muaj ob txoj kev sib pauv hauv theem ntawm 90 degrees yog hloov thiab qhov tso zis tshwm muaj ob yam puv ntaws thiab theem variations. Nyob rau hauv view ntawm lub fact tias ob qho tib si amplitude thiab theem variations yog nws muaj peev xwm kuj yuav suav hais tias yog raws li ib tug sib tov ntawm amplitude thiab theem tes taws los piav.
Feem ntau qhov qis q Qum ntsib yog 16QAM. Yog vim li cas qhov no yog qhov qis qis tshaj li niaj zaus ntsib yog tias 2QAM yog tib yam li binary theem-ua haujlwm tseem ceeb, BPSK, thiab 4QAM yog tib yam li quadrature theem-ua haujlwm tseem ceeb, QPSK. Txuas ntxiv 8QAM tsis siv ntau. Qhov no yog vim kev ua yuam kev hauv 8QAM yog tib yam li ntawm 16QAM - nws tsuas yog li 0.5 dB zoo dua thiab cov ntaub ntawv tus nqi tsuas yog peb lub quarter ntawm 16QAM. Qhov no tshwm sim los ntawm cov rectangular, es tsis yog square duab ntawm lub constellation.
DIBSYS IPQ6250 yog ib tiam tshiab ntawm qhov kev hloov siab & siab ceev Edge QAM modulator sib txuas ua ke txais TS-tshaj-UDP / RTP, 16/32/64/128 / 256QAM modulation ect. Nws txhawb nqa txog 48 QAM raws li siv peb sab nraws 16 QAM modules, txhua QAM modules uas txhawb nqa txog ob Gigabit tooj liab interfaces.Nrog IPQ6250, cable operators yuav ensured tias lawv yuav muaj scalable, txhim khu kev qha, high school video stream cov kev pab rau xyoo mus rau yav tom ntej. Nws tuaj yeem siv rau cable DTV lub taub hau-xaus, sub lub qhov xaus thiab VOD tes hauj lwm.
