Cov TV Front-end khoom Debugging txoj kev
Nov 25, 2014
Nyob hauv debugging cov tshooj TV hauv lub taub hau kawg khoom, mas mus tso zis qib uas cov modulator thiab cov modulator kho zaus.
(1) tso zis lub qhov tso zis modulator co tes theem kev haum nyob rau ib sab pem hauv ntej thaum xaus ntawm lawv, cable TV analog thiab cov chaw yuav sib xyaw outputs. Vim lawv cov tswvyim tes taws los piav ntau, thiab vim li no, lawv cov zis theem tseem tseem txawv. Cab kuj modulated analog TV yog VSB; i.e., residual sideband amplitude tes taws los piav lawv; thiab cov cable 64 QAMM modulated, ob chav sideband coj tus yam ntxwv zoo, lawv ncov hwj huam thiab hwj huam nruab nrab txawv, raws li lus teb thiab cov kev kawm txawj xwb, xws li cov modulator tso zis qib dua kev analog modulator tso zis ntau lawm ntawm 10dB. Ntxiv mus, cov zis analog thiab analog raws, raws cov, thiab cov qib uas luaj li cas thiab flatness ncaj qha rau lub cev metrics network. Nyob rau hauv, cov sib ntxiv mus tso zis ntau theem Tswjhwm Circuit Court tsim, lub siab thiab tsis muaj tswj qhov luaj li cas txawv ntawm qhov raws me me, lub zog flatness sib txawv kawm suab nrov zoo zoo. Kev front-end analog thiab analog uas nyob ib sab channel qib sib txawv ntawm cov thiab cov uas nyob ib sab channel yuav tsum tsis tshaj ± 0.5dBμV.
(2) lub zaus ntawm lub chaw hais saum toj no vim cov tes taws los piav ntau analog raws thiab raws cov modulator, thiab vim li no lawv tej chaw tso zis ntau zaus mas sib txawv. Analog TV modulator zaus yog muab los ntawm qhov pom kev zoo daim nyias ev zaus, thiab lub zaus ntawm qhov cov TV modulator tau raws li qhov chaw zaus ntawm cov channel, nws tseem ceeb heev.
