He aha ka MER & BER i ka Pūnaehana TV Cable Digital?

He aha ka MER & BER i ka Pūnaehana TV Cable Digital?

MER: ʻO ka lākiō hewa modulation, ʻo ia ka ratio o ka waiwai kūpono o ka nui vector i ka waiwai kūpono o ka nui o ka hewa ma ke kiʻikuhi constellation (ka lakio o ka huinahā o ka nui vector kūpono i ka huinahā o ka nui vector hala) . ʻO ia kekahi o nā hōʻailona nui e ana i ka maikaʻi o nā hōʻailona TV kikohoʻe. He mea koʻikoʻi loa ia i nā hualoaʻa ana logarithmic o ka distortion superimposed ma ka hōʻailona modulation kikohoʻe. Ua like ia me ka ratio signal-to-noise a i ʻole carrier-to-noise ratio i hoʻohana ʻia ma ka ʻōnaehana analog. He ʻōnaehana hoʻokolokolo He ʻāpana koʻikoʻi o ka hoʻomanawanui ʻole. Nā hōʻailona like ʻē aʻe e like me BER bit error rate, C/N carrier-to-noise ratio, power level average power, constellation diagram, etc.

Hōʻike ʻia ka waiwai o MER ma dB, a ʻoi aku ka nui o ka waiwai o MER, ʻoi aku ka maikaʻi o ka hōʻailona. ʻOi aku ka maikaʻi o ka hōʻailona, ​​ʻoi aku ka pili o nā hōʻailona modulated i ke kūlana kūpono, a me ka hope. Hōʻike ka hopena hoʻāʻo o MER i ka hiki o ka mea hoʻokipa kikohoʻe ke hoʻihoʻi i ka helu binary, a aia kahi ʻano hōʻailona-a-noise ratio (S/N) e like me ka hōʻailona baseband. Hoʻopukaʻia ka hōʻailona QAM-modulated mai ka hopena mua a komo i ka home ma o ka pūnaewele komo. E emi mālie ka hōʻailona MER. I ka hihia o ka constellation diagram 64QAM, ʻo 23.5dB ka waiwai paepae empirical o MER, a ma 256QAM he 28.5dB (pono ka puka mua-hope inā ʻoi aku ia ma mua o 34dB, hiki iā ia ke hōʻoia i ke komo ʻana o ka hōʻailona i ka home maʻamau. , akā, ʻaʻole ia e hoʻokaʻawale i nā mea ʻino i hana ʻia e ka maikaʻi o ke kaula hoʻouna a i ʻole ka hope sub-front). Inā ʻoi aku ka haʻahaʻa ma mua o kēia waiwai, ʻaʻole e laka ʻia ke kiʻikuhi o nā hōkū. MER hōʻike mua-hope modulation pono puka: No 64/256QAM, mua-hope > 38dB, sub-mua-hope > 36dB, optical node > 34dB, amplifier > 34dB (kekona he 33dB), mea hoʻohana hope > 31dB (kekona he 33dB ), ma luna o 5 Hoʻohana pinepine ʻia kahi kī MER no ka ʻimi ʻana i nā pilikia laina TV.

64 &256QAM

Manaʻo ʻia ka manaʻo nui o MER MER ma ke ʻano he ana SNR, a ʻo ke ʻano o MER:

①. Loaʻa iā ia nā ʻano pōʻino like ʻole i ka hōʻailona: ka walaʻau, ka leaka o ka mea lawe, IQ amplitude imbalance, a me ka walaʻau.

②. Hōʻike ia i ka hiki o nā hana kikohoʻe e hoʻihoʻi i nā helu binary; hōʻike ia i ke kiʻekiʻe o ka pōʻino i nā hōʻailona TV kikohoʻe ma hope o ka hoʻouna ʻia ʻana ma o ka pūnaewele.

③. ʻO SNR kahi ʻāpana baseband, a ʻo MER kahi ʻāpana lekiō.

Ke hoʻohaʻahaʻa ka maikaʻi o ka hōʻailona i kekahi pae, e hoʻololi hewa ʻia nā hōʻailona. I kēia manawa, piʻi ka helu bit error rate BER. BER (Bit Error Rate): Bit error rate, i wehewehe ʻia e like me ka ratio o ka helu o nā ʻāpana hewa i ka huina o nā ʻāpana. No nā hōʻailona kikohoʻe binary, ʻoiai ua hoʻouna ʻia nā bits binary, ua kapa ʻia ka hapa hapa hapa ʻo ka bit error rate (BER).

 64 qam-01.

BER = Hapa Kuhikuhi/Ka huina Bit Rahi.

Hōʻike ʻia ʻo BER ma ka notation ʻepekema, a ʻo ka haʻahaʻa o ka BER, ʻoi aku ka maikaʻi. Ke maikaʻi loa ka maikaʻi o ka hōʻailona, ​​ua like nā helu BER ma mua a ma hope o ka hoʻoponopono hewa; akā i ka hihia o kekahi keakea, ʻokoʻa nā helu BER ma mua a ma hope o ka hoʻoponopono hewa ʻana, a ma hope o ka hoʻoponopono hewa He haʻahaʻa ka hapa hapa. Ke 2×10-4 ka hapa hapa, ʻike ʻia ka hapa mosaic i kekahi manawa, akā hiki ke nānā ʻia; ʻo ka BER koʻikoʻi ʻo 1 × 10-4, ʻike ʻia ka nui o nā mosaics, a ʻike ʻia ka pāʻani kiʻi i ka manawa pōkole; ʻAʻole hiki ke nānā ʻia ka BER ʻoi aku ma mua o 1 × 10-3. kiai. ʻO ka helu helu BER wale nō ka waiwai kuhikuhi a ʻaʻole i hōʻike piha i ke kūlana o nā lako pūnaewele holoʻokoʻa. ʻO kekahi manawa ma muli o ka piʻi koke ʻana ma muli o ke keakea koke ʻana, ʻoiai ʻo MER ke kū'ē loa. Hiki ke hoʻohana ʻia ke kaʻina holoʻokoʻa ma ke ʻano he ʻikepili kuhi hewa. No laila, hiki i ka MER ke hāʻawi i ka ʻōlelo aʻo mua no nā hōʻailona. Ke emi ka maikaʻi o ka hōʻailona, ​​e emi ana ka MER. Me ka piʻi ʻana o ka walaʻau a me ka hoʻopili ʻana i kekahi ʻano, e emi mālie ka MER, ʻoiai ʻaʻole i loli ka BER. Ke piʻi aʻe ke keʻakeʻa i kekahi ʻano, hoʻomaka ka MER E hoʻomaka ka BER e hōʻemi i ka wā e hāʻule mau ai ka MER. Ke hāʻule ka MER i ka pae paepae, e hāʻule nui ka BER.

 

 


Ka manawa hoʻouna: Feb-23-2023

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