{"id":3512,"date":"2025-12-02T00:00:00","date_gmt":"2025-12-02T00:00:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/glossary\/tdecq-pam4-optical-transmitter-quality-metric\/"},"modified":"2026-06-22T04:27:32","modified_gmt":"2026-06-22T04:27:32","slug":"tdecq-pam4-optical-transmitter-quality-metric","status":"publish","type":"post","link":"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/tdecq-pam4-optical-transmitter-quality-metric","title":{"rendered":"Hi\u1ec3u v\u1ec1 TDECQ: Ch\u1ec9 S\u1ed1 Ch\u1ea5t L\u01b0\u1ee3ng Ph\u00e1t T\u00edn Hi\u1ec7u PAM4 Quan Tr\u1ecdng cho M\u00f4-\u0111un Quang"},"content":{"rendered":"
\"What<\/figure>\n\n\n\n

\ud83d\udccc TDECQ (Transmitter and Dispersion Eye Closure Quaternary) l\u00e0 g\u00ec?<\/h2>\n\n\n\n

TDECQ l\u00e0 vi\u1ebft t\u1eaft c\u1ee7a Transmitter and Dispersion Eye Closure Quaternary (\u0110\u00f3ng k\u00edn m\u1eaft ph\u00e1t x\u1ea1 v\u00e0 ph\u00e2n t\u00e1n b\u1eadc b\u1ed1n)<\/em>. \u0110\u00e2y l\u00e0 m\u1ed9t ph\u00e9p \u0111o chu\u1ea9n h\u00f3a \u2014 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a trong h\u1ecd ti\u00eau chu\u1ea9n IEEE 802.3 \u2014 d\u00f9ng \u0111\u1ec3 \u0111\u1ecbnh l\u01b0\u1ee3ng ch\u1ea5t l\u01b0\u1ee3ng quang h\u1ecdc c\u1ee7a m\u1ed9t PAM4<\/a> b\u1ed9 ph\u00e1t khi \u0111i\u1ec1u khi\u1ec3n m\u1ed9t li\u00ean k\u1ebft quang.<\/p>\n\n\n\n

Trong th\u1ef1c t\u1ebf, TDECQ bi\u1ec3u th\u1ecb m\u1ee9c c\u00f4ng su\u1ea5t quang b\u1ed5 sung (ho\u1eb7c bi\u00ean d\u1ef1 ph\u00f2ng) c\u1ea7n thi\u1ebft cho m\u1ed9t b\u1ed9 ph\u00e1t th\u1ef1c t\u1ebf \u2014 sau khi t\u00ednh \u0111\u1ebfn nhi\u1ec5u, nhi\u1ec5u gi\u1eefa c\u00e1c k\u00fd hi\u1ec7u (ISI)<\/a>, ph\u00e2n t\u00e1n v\u00e0 c\u00e1c suy hao kh\u00e1c \u2014 \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111\u1ed9 m\u1edf \u201cm\u1eaft\u201d t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi b\u1ed9 ph\u00e1t l\u00fd t\u01b0\u1edfng. Gi\u00e1 tr\u1ecb TDECQ th\u1ea5p h\u01a1n cho th\u1ea5y ch\u1ea5t l\u01b0\u1ee3ng t\u00edn hi\u1ec7u t\u1ed1t h\u01a1n v\u00e0 th\u01b0\u1eddng t\u01b0\u01a1ng quan v\u1edbi m\u1ee9c t\u1ef7 l\u1ec7 l\u1ed7i bit
<\/a>.<\/p>\n\n\n\n

Do c\u00e1c li\u00ean k\u1ebft t\u1ed1c \u0111\u1ed9 cao hi\u1ec7n \u0111\u1ea1i ng\u00e0y c\u00e0ng s\u1eed d\u1ee5ng \u0111i\u1ec1u ch\u1ebf PAM4 (v\u00ed d\u1ee5: 50G, 100G, 200G, 400G), TDECQ \u0111\u00e3 tr\u1edf th\u00e0nh ch\u1ec9 s\u1ed1 then ch\u1ed1t th\u1ef1c t\u1ebf nh\u1eb1m \u0111\u1ea3m b\u1ea3o s\u1ef1 tu\u00e2n th\u1ee7 c\u1ee7a b\u1ed9 ph\u00e1t v\u00e0 \u0111\u1ed9 tin c\u1eady c\u1ee7a li\u00ean k\u1ebft.<\/p>\n\n\n\n

\ud83d\udccc V\u00ec sao C\u00e1c Ch\u1ec9 S\u1ed1 Truy\u1ec1n Th\u1ed1ng Kh\u00f4ng C\u00f2n \u0110\u1ee7<\/h2>\n\n\n\n

S\u1ef1 Chuy\u1ec3n D\u1ecbch T\u1eeb NRZ Sang PAM4<\/h3>\n\n\n\n

\u1ede c\u00e1c th\u1ebf h\u1ec7 tr\u01b0\u1edbc d\u1ef1a tr\u00ean NRZ<\/a> (t\u00edn hi\u1ec7u hai m\u1ee9c), c\u00e1c b\u1ed9 ph\u00e1t quang \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 b\u1eb1ng t\u1ef7 s\u1ed1 t\u1eaft s\u00e1ng (extinction ratio), OMA ngo\u00e0i c\u00f9ng<\/a>, v\u00e0 bi\u00ean d\u1ef1 ph\u00f2ng m\u1eb7t n\u1ea1 m\u1eaft (eye-mask margin). \u0110\u1ed1i v\u1edbi c\u00e1c ng\u00e2n s\u00e1ch li\u00ean k\u1ebft cao h\u01a1n, \u0111\u00f4i khi ng\u01b0\u1eddi ta s\u1eed d\u1ee5ng TDP (Transmitter and Dispersion Penalty \u2013 T\u1ed5n hao do b\u1ed9 ph\u00e1t v\u00e0 ph\u00e2n t\u00e1n). Tuy nhi\u00ean, vi\u1ec7c ki\u1ec3m tra TDP \u0111\u00f2i h\u1ecfi c\u1ea5u h\u00ecnh ph\u1ee9c t\u1ea1p v\u00e0 t\u1ed1n nhi\u1ec1u th\u1eddi gian.<\/p>\n\n\n\n

V\u1edbi PAM4, t\u00edn hi\u1ec7u c\u00f3 b\u1ed1n m\u1ee9c, l\u00e0m thu h\u1eb9p bi\u1ec3u \u0111\u1ed3 m\u1eaft v\u00e0 khi\u1ebfn c\u00e1c ch\u1ec9 s\u1ed1 m\u1eb7t n\u1ea1 m\u1eaft truy\u1ec1n th\u1ed1ng tr\u1edf n\u00ean kh\u00f4ng \u0111\u1ee7. Nhi\u1ec5u, ISI, ph\u00e2n t\u00e1n v\u00e0 s\u1ef1 ch\u00eanh l\u1ec7ch gi\u1eefa c\u00e1c m\u1ee9c con c\u1ee7a m\u1eaft \u0111\u00f2i h\u1ecfi m\u1ed9t ch\u1ec9 s\u1ed1 m\u1ea1nh m\u1ebd v\u00e0 l\u1eb7p l\u1ea1i \u0111\u01b0\u1ee3c h\u01a1n \u2014 \u0111\u00f3 ch\u00ednh l\u00e0 TDECQ.<\/p>\n\n\n\n

\"TDECQ\"<\/figure>\n\n\n\n

\ud83d\udccc C\u00e1ch \u0110\u1ecbnh Ngh\u0129a V\u00e0 \u0110o L\u01b0\u1eddng TDECQ<\/h2>\n\n\n\n

Kh\u00e1i Ni\u1ec7m C\u01a1 B\u1ea3n \u2014 T\u1ed5n Hao C\u00f4ng Su\u1ea5t So V\u1edbi B\u1ed9 Ph\u00e1t L\u00fd T\u01b0\u1edfng<\/h3>\n\n\n\n

TDECQ \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a l\u00e0 m\u1ee9c c\u00f4ng su\u1ea5t quang b\u1ed5 sung (\u0111\u01a1n v\u1ecb dB) m\u00e0 m\u1ed9t b\u1ed9 ph\u00e1t \u0111\u01b0\u1ee3c \u0111o c\u1ea7n c\u00f3 \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111\u1ed9 m\u1edf m\u1eaft theo chi\u1ec1u d\u1ecdc (sau khi c\u00e2n b\u1eb1ng) t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi b\u1ed9 ph\u00e1t l\u00fd t\u01b0\u1edfng d\u01b0\u1edbi c\u00f9ng \u0111i\u1ec1u ki\u1ec7n li\u00ean k\u1ebft tham chi\u1ebfu.<\/p>\n\n\n\n

Trong qu\u00e1 tr\u00ecnh \u0111o, \u0111\u1ea7u ra c\u1ee7a b\u1ed9 ph\u00e1t \u0111\u01b0\u1ee3c thu b\u1edfi b\u1ed9 chuy\u1ec3n \u0111\u1ed5i quang\u2013\u0111i\u1ec7n tham chi\u1ebfu v\u00e0 b\u1ed9 c\u00e2n b\u1eb1ng tham chi\u1ebfu. C\u00e1c thu\u1eadt to\u00e1n t\u00ednh to\u00e1n TDECQ d\u1ef1a tr\u00ean bi\u00ean \u0111\u1ed9 d\u1ea1ng s\u00f3ng, nhi\u1ec5u, ISI v\u00e0 ph\u00e2n t\u00e1n.<\/p>\n\n\n\n

C\u00e1c Gi\u1edbi H\u1ea1n TDECQ Ti\u00eau Bi\u1ec3u Trong C\u00e1c Ti\u00eau Chu\u1ea9n Ng\u00e0nh<\/h3>\n\n\n\n

\u0110\u1ed1i v\u1edbi c\u00e1c ti\u00eau chu\u1ea9n nh\u01b0 50GBASE-FR \/ 50GBASE-LR<\/a> \/ 100GBASE-DR, gi\u1edbi h\u1ea1n t\u1ed1i \u0111a TDECQ th\u01b0\u1eddng v\u00e0o kho\u1ea3ng 3,2\u20133,4\u202fdB. Vi\u1ec7c \u0111\u00e1p \u1ee9ng c\u00e1c gi\u1edbi h\u1ea1n n\u00e0y \u0111\u1ea3m b\u1ea3o bi\u00ean d\u1ef1 ph\u00f2ng theo chi\u1ec1u d\u1ecdc \u0111\u1ee7 l\u1edbn \u0111\u1ec3 b\u1ed9 thu ho\u1ea1t \u0111\u1ed9ng \u1ed5n \u0111\u1ecbnh.<\/p>\n\n\n\n

\ud83d\udccc TDECQ Ph\u1ea3n \u00c1nh \u0110i\u1ec1u G\u00ec \u2014 Ph\u1ea1m Vi V\u00e0 H\u1ea1n Ch\u1ebf C\u1ee7a N\u00f3<\/h2>\n\n\n\n

\u25b7 Nh\u1eefng Y\u1ebfu T\u1ed1 TDECQ \u0110\u00e1nh Gi\u00e1<\/h3>\n\n\n\n