{"id":5813,"date":"2025-07-11T00:00:00","date_gmt":"2025-07-11T00:00:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/knowledge-center\/what-is-the-difference-between-nrz-and-pam4\/"},"modified":"2026-06-22T09:06:48","modified_gmt":"2026-06-22T09:06:48","slug":"what-is-the-difference-between-nrz-and-pam4","status":"publish","type":"post","link":"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/what-is-the-difference-between-nrz-and-pam4","title":{"rendered":"NRZ so v\u1edbi PAM4: Hi\u1ec3u r\u00f5 nh\u1eefng kh\u00e1c bi\u1ec7t ch\u00ednh"},"content":{"rendered":"<figure class=\"wp-block-image aligncenter size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c.webp\" alt=\"What is the difference between NRZ and PAM4?\" class=\"wp-image-5807\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/05091a803b6a4dbdbdb66f8a4b45136c-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Nh\u1eefng kh\u00e1c bi\u1ec7t ch\u00ednh gi\u1eefa PAM4 v\u00e0 NRZ<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Kh\u00e1m ph\u00e1 s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 \u0111i\u1ec1u ch\u1ebf PAM4 v\u00e0 NRZ cho c\u00e1c m\u1ea1ng hi\u1ec7n \u0111\u1ea1i.<\/p>\n\n\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<colgroup><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><\/colgroup><tbody><tr><th colspan=\"1\" rowspan=\"1\"><p><strong>\u0110\u1eb7c t\u00ednh<\/strong><\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p><strong>NRZ (Non-Return to Zero \u2013 Kh\u00f4ng quay v\u1ec1 m\u1ee9c kh\u00f4ng)<\/strong><\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p><strong>(\u0110i\u1ec1u ch\u1ebf bi\u00ean \u0111\u1ed9 xung 4 m\u1ee9c)<\/strong><\/p><\/th><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>M\u1ee9c<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>2 (v\u00ed d\u1ee5: Th\u1ea5p = 0, Cao = 1)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>4 (v\u00ed d\u1ee5: L0 = 00, L1 = 01, L2 = 10, L3 = 11)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>1<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>2<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Hi\u1ec7u su\u1ea5t t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p h\u01a1n (T\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u = T\u1ed1c \u0111\u1ed9 k\u00fd hi\u1ec7u)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n (T\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u = 2 \u00d7 T\u1ed1c \u0111\u1ed9 k\u00fd hi\u1ec7u)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>T\u1ed1c \u0111\u1ed9 k\u00fd hi\u1ec7u (Baud) cho c\u00f9ng t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n (v\u00ed d\u1ee5: 56 GBaud cho 56 Gbps)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p h\u01a1n (v\u00ed d\u1ee5: 28 GBaud cho 56 Gbps)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>\u0110\u1ed9 nh\u1ea1y v\u1edbi nhi\u1ec5u<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p h\u01a1n (M\u1edf m\u1eaft l\u1edbn h\u01a1n, bi\u00ean d\u1ef1 tr\u1eef SNR cao h\u01a1n)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n (M\u1edf m\u1eaft nh\u1ecf h\u01a1n, bi\u00ean d\u1ef1 tr\u1eef SNR th\u1ea5p h\u01a1n)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>\u0110\u1ed9 ph\u1ee9c t\u1ea1p tri\u1ec3n khai<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Lower<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n (Y\u00eau c\u1ea7u x\u1eed l\u00fd t\u00edn hi\u1ec7u s\u1ed1 DSP v\u00e0 m\u00e3 h\u00f3a s\u1eeda l\u1ed7i m\u1ea1nh FEC)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>C\u00f4ng su\u1ea5t ti\u00eau th\u1ee5 trung b\u00ecnh tr\u00ean m\u1ed7i bit<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p h\u01a1n (C\u00f4ng ngh\u1ec7 tr\u01b0\u1edfng th\u00e0nh)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n (Chi ph\u00ed do \u0111\u1ed9 ph\u1ee9c t\u1ea1p)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>C\u00e1c t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u ch\u1ee7 \u0111\u1ea1o<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>\u2264 25 Gbps tr\u00ean m\u1ed7i k\u00eanh (v\u00ed d\u1ee5: SFP+ 10G, 25G)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>\u2265 50 Gbps tr\u00ean m\u1ed7i k\u00eanh (v\u00ed d\u1ee5: 100G, 200G, 400G, 800G)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>C\u00e1c \u1ee9ng d\u1ee5ng ch\u1ee7 ch\u1ed1t<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Giao di\u1ec7n c\u0169 (10G\/25G), kho\u1ea3ng c\u00e1ch ng\u1eafn<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Trung t\u00e2m d\u1eef li\u1ec7u t\u1ed1c \u0111\u1ed9 cao (\u2265100G), \u0111i\u1ec7n to\u00e1n hi\u1ec7u n\u0103ng cao (HPC), c\u1ee5m AI\/ML, \u0111\u01b0\u1eddng truy\u1ec1n tr\u01b0\u1edbc\/m\u1ea1ng trung t\u00e2m 5G<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y m\u1ea1ng \u0111ang thay \u0111\u1ed5i nhanh ch\u00f3ng khi trung t\u00e2m d\u1eef li\u1ec7u c\u1ea7n t\u1ed1c \u0111\u1ed9 cao h\u01a1n. <strong>PAM4 so v\u1edbi NRZ<\/strong> Cu\u1ed9c tranh lu\u1eadn n\u00e0y r\u1ea5t quan tr\u1ecdng v\u00ec PAM4 truy\u1ec1n hai bit cho m\u1ed7i k\u00fd hi\u1ec7u, trong khi NRZ ch\u1ec9 truy\u1ec1n m\u1ed9t bit. S\u1ef1 thay \u0111\u1ed5i n\u00e0y gi\u00fap hi\u1ec7u su\u1ea5t b\u0103ng th\u00f4ng t\u0103ng g\u1ea5p \u0111\u00f4i cho Ethernet m\u1edbi m\u00e0 kh\u00f4ng c\u1ea7n m\u1edf r\u1ed9ng b\u0103ng th\u00f4ng k\u00eanh. Trong trung t\u00e2m d\u1eef li\u1ec7u, vi\u1ec7c so s\u00e1nh PAM4 v\u00e0 NRZ r\u1ea5t quan tr\u1ecdng v\u00ec PAM4 s\u1eed d\u1ee5ng b\u1ed1n m\u1ee9c bi\u00ean \u0111\u1ed9, c\u00f2n NRZ ch\u1ec9 d\u00f9ng hai m\u1ee9c. Khi m\u1ea1ng tr\u1edf n\u00ean nhanh h\u01a1n, \u0111i\u1ec1u ch\u1ebf PAM4 gi\u00fap truy\u1ec1n d\u1eef li\u1ec7u nhanh v\u00e0 hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 \u0110i\u1ec3m n\u1ed5i b\u1eadt<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><strong>PAM4<\/strong> Truy\u1ec1n hai bit trong m\u1ed7i k\u00fd hi\u1ec7u. N\u00f3 s\u1eed d\u1ee5ng b\u1ed1n m\u1ee9c \u0111i\u1ec7n \u00e1p. \u0110i\u1ec1u n\u00e0y gi\u00fap t\u1ed1c \u0111\u1ed9 truy\u1ec1n d\u1eef li\u1ec7u t\u0103ng g\u1ea5p \u0111\u00f4i so v\u1edbi NRZ. NRZ ch\u1ec9 truy\u1ec1n m\u1ed9t bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u v\u00e0 ch\u1ec9 s\u1eed d\u1ee5ng hai m\u1ee9c \u0111i\u1ec7n \u00e1p.<\/p><\/li><li><p><strong>NRZ<\/strong> C\u00f3 t\u00edn hi\u1ec7u m\u1ea1nh h\u01a1n. \u00cdt nhi\u1ec5u h\u01a1n v\u00e0 ti\u00eau th\u1ee5 \u00edt n\u0103ng l\u01b0\u1ee3ng h\u01a1n. \u0110i\u1ec1u n\u00e0y l\u00e0m cho n\u00f3 d\u1ec5 tri\u1ec3n khai h\u01a1n. N\u00f3 ho\u1ea1t \u0111\u1ed9ng t\u1ed1t h\u01a1n tr\u00ean kho\u1ea3ng c\u00e1ch d\u00e0i ho\u1eb7c m\u1ea1ng t\u1ed1c \u0111\u1ed9 th\u1ea5p.<\/p><\/li><li><p>PAM4 ho\u1ea1t \u0111\u1ed9ng t\u1ed1t nh\u1ea5t tr\u00ean c\u00e1c li\u00ean k\u1ebft ng\u1eafn v\u00e0 t\u1ed1c \u0111\u1ed9 cao. N\u00f3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong Ethernet 400G v\u00e0 trung t\u00e2m d\u1eef li\u1ec7u. N\u00f3 y\u00eau c\u1ea7u k\u1ef9 thu\u1eadt s\u1eeda l\u1ed7i \u0111\u1eb7c bi\u1ec7t v\u00e0 ti\u00eau th\u1ee5 nhi\u1ec1u n\u0103ng l\u01b0\u1ee3ng h\u01a1n.<\/p><\/li><li><p>B\u1ea1n l\u1ef1a ch\u1ecdn gi\u1eefa PAM4 v\u00e0 NRZ d\u1ef1a tr\u00ean m\u1ea1ng c\u1ee7a m\u00ecnh. H\u00e3y c\u00e2n nh\u1eafc c\u00e1c y\u1ebfu t\u1ed1 nh\u01b0 t\u1ed1c \u0111\u1ed9, kho\u1ea3ng c\u00e1ch, chi ph\u00ed v\u00e0 nhu c\u1ea7u t\u01b0\u01a1ng lai.<\/p><\/li><li><p>Vi\u1ec7c s\u1eed d\u1ee5ng c\u1ea3 PAM4 v\u00e0 NRZ trong c\u00f9ng m\u1ed9t m\u1ea1ng c\u00f3 th\u1ec3 mang l\u1ea1i l\u1ee3i \u00edch. N\u00f3 c\u00e2n b\u1eb1ng gi\u1eefa t\u1ed1c \u0111\u1ed9 v\u00e0 \u0111\u1ed9 tin c\u1eady, \u0111\u1ed3ng th\u1eddi h\u1ed7 tr\u1ee3 s\u1eb5n s\u00e0ng cho c\u00e1c n\u00e2ng c\u1ea5p trong t\u01b0\u01a1ng lai.<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 C\u01a1 b\u1ea3n v\u1ec1 \u0111i\u1ec1u ch\u1ebf<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >NRZ l\u00e0 g\u00ec?<\/h3>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"486\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1.webp\" alt=\"NRZ encoding\" class=\"wp-image-5808\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1-300x122.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1-1024x415.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1-768x311.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/ce3795470145420dba9b9d02e500e6f1-18x7.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/understanding-non-return-to-zero-in-digital-communication\/\"><strong>NRZ<\/strong><\/a> l\u00e0 m\u1ed9t c\u00e1ch \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 g\u1eedi t\u00edn hi\u1ec7u. T\u1eeb vi\u1ebft t\u1eaft c\u1ee7a n\u00f3 l\u00e0 <strong>kh\u00f4ng quay tr\u1edf l\u1ea1i m\u1ee9c zero<\/strong>. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y s\u1eed d\u1ee5ng hai \u0111i\u1ec7n \u00e1p \u0111\u1ec3 bi\u1ec3u th\u1ecb d\u1eef li\u1ec7u nh\u1ecb ph\u00e2n. Gi\u00e1 tr\u1ecb \u20181\u2019 \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb b\u1eb1ng \u0111i\u1ec7n \u00e1p cao, c\u00f2n gi\u00e1 tr\u1ecb \u20180\u2019 \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb b\u1eb1ng \u0111i\u1ec7n \u00e1p th\u1ea5p. T\u00edn hi\u1ec7u kh\u00f4ng quay tr\u1edf l\u1ea1i m\u1ee9c zero gi\u1eefa c\u00e1c bit. \u0110i\u1ec1u n\u00e0y gi\u00fap vi\u1ec7c hi\u1ec3u t\u00edn hi\u1ec7u tr\u1edf n\u00ean d\u1ec5 d\u00e0ng h\u01a1n. Trong NRZ \u0111\u01a1n c\u1ef1c, \u20181\u2019 l\u00e0 \u0111i\u1ec7n \u00e1p d\u01b0\u01a1ng v\u00e0 \u20180\u2019 l\u00e0 0 v\u00f4n. Trong NRZ l\u01b0\u1ee1ng c\u1ef1c, t\u00edn hi\u1ec7u chuy\u1ec3n \u0111\u1ed5i gi\u1eefa \u0111i\u1ec7n \u00e1p d\u01b0\u01a1ng v\u00e0 \u00e2m. <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px 0px 4px;\"><strong>Hai m\u1ee9c:<\/strong> N\u00f3 s\u1eed d\u1ee5ng hai m\u1ee9c \u0111i\u1ec7n \u00e1p (\u0111i\u1ec7n) ho\u1eb7c c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng (quang) ri\u00eang bi\u1ec7t.<\/p><ul><li><p style=\"margin: 0px;\">M\u1ee9c cao th\u01b0\u1eddng bi\u1ec3u th\u1ecb gi\u00e1 tr\u1ecb logic \u20181\u2019.<\/p><\/li><li><p style=\"margin: 0px;\">M\u1ee9c th\u1ea5p bi\u1ec3u th\u1ecb gi\u00e1 tr\u1ecb logic \u20180\u2019.<\/p><\/li><\/ul><\/li><li><p style=\"margin: 0px;\"><strong>Ho\u1ea1t \u0111\u1ed9ng \u0111\u01a1n gi\u1ea3n:<\/strong> M\u1ed7i chu k\u1ef3 k\u00fd hi\u1ec7u truy\u1ec1n \u0111i ho\u1eb7c \u20181\u2019 ho\u1eb7c \u20180\u2019. T\u00edn hi\u1ec7u kh\u00f4ng quay tr\u1edf l\u1ea1i tr\u1ea1ng th\u00e1i \u201czero\u201d trung t\u00ednh gi\u1eefa c\u00e1c bit c\u00f3 c\u00f9ng gi\u00e1 tr\u1ecb (do \u0111\u00f3 c\u00f3 t\u00ean g\u1ecdi \u201cKh\u00f4ng quay tr\u1edf l\u1ea1i m\u1ee9c zero\u201d).<\/p><\/li><li><p style=\"margin: 0px;\"><strong>\u01afu \u0111i\u1ec3m:<\/strong> S\u1ef1 \u0111\u01a1n gi\u1ea3n khi\u1ebfn NRZ tr\u1edf n\u00ean b\u1ec1n b\u1ec9 v\u00e0 t\u01b0\u01a1ng \u0111\u1ed1i d\u1ec5 tri\u1ec3n khai v\u1edbi m\u1ee9c ti\u00eau th\u1ee5 c\u00f4ng su\u1ea5t th\u1ea5p h\u01a1n c\u0169ng nh\u01b0 y\u00eau c\u1ea7u x\u1eed l\u00fd t\u00edn hi\u1ec7u \u00edt ph\u1ee9c t\u1ea1p h\u01a1n. N\u00f3 mang l\u1ea1i \u0111\u1ed9 to\u00e0n v\u1eb9n t\u00edn hi\u1ec7u xu\u1ea5t s\u1eafc \u1edf t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u th\u1ea5p.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>H\u1ea1n ch\u1ebf:<\/strong> Tuy nhi\u00ean, hi\u1ec7u qu\u1ea3 c\u1ee7a n\u00f3 \u0111\u1ea1t \u0111\u1ebfn gi\u1edbi h\u1ea1n. \u0110\u1ec3 t\u0103ng g\u1ea5p \u0111\u00f4i t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u, b\u1ea1n c\u1ea7n t\u0103ng g\u1ea5p \u0111\u00f4i t\u1ed1c \u0111\u1ed9 k\u00fd hi\u1ec7u (t\u1ed1c \u0111\u1ed9 baud). Vi\u1ec7c t\u0103ng g\u1ea5p \u0111\u00f4i t\u1ed1c \u0111\u1ed9 baud l\u00e0m gia t\u0103ng \u0111\u00e1ng k\u1ec3 suy hao t\u00edn hi\u1ec7u do t\u1ed5n th\u1ea5t k\u00eanh, nhi\u1ec5u v\u00e0 gh\u00e9p k\u00eanh ch\u00e9o, khi\u1ebfn vi\u1ec7c \u00e1p d\u1ee5ng tr\u1edf n\u00ean kh\u00f4ng kh\u1ea3 thi v\u01b0\u1ee3t qu\u00e1 kho\u1ea3ng ~25\u201328 Gigabaud tr\u00ean m\u1ed7i lane trong c\u00e1c \u1ee9ng d\u1ee5ng ph\u1ed5 bi\u1ebfn.<\/p><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" >PAM4 l\u00e0 g\u00ec?<\/h3>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"516\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b.webp\" alt=\"PAM4 encoding\" class=\"wp-image-5809\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b-300x129.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b-1024x440.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b-768x330.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/8766e10c7cab415784322b28ebf4f58b-18x8.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/what-is-pam4-four-level-pulse-amplitude-modulation-basics\/\"><strong>PAM4<\/strong><\/a> l\u00e0 m\u1ed9t c\u00e1ch \u0111\u1ec3 g\u1eedi nhi\u1ec1u d\u1eef li\u1ec7u h\u01a1n c\u00f9ng l\u00fac. T\u1eeb vi\u1ebft t\u1eaft c\u1ee7a n\u00f3 l\u00e0 <strong>\u0111i\u1ec1u ch\u1ebf bi\u00ean \u0111\u1ed9 xung 4 m\u1ee9c<\/strong>. N\u00f3 s\u1eed d\u1ee5ng b\u1ed1n m\u1ee9c \u0111i\u1ec7n \u00e1p \u0111\u1ec3 bi\u1ec3u th\u1ecb hai bit trong m\u1ed7i k\u00fd hi\u1ec7u. Nh\u1edd \u0111\u00f3, b\u1ea1n c\u00f3 th\u1ec3 g\u1eedi l\u01b0\u1ee3ng d\u1eef li\u1ec7u g\u1ea5p \u0111\u00f4i so v\u1edbi NRZ trong c\u00f9ng m\u1ed9t kho\u1ea3ng th\u1eddi gian. PAM4 l\u00e0 m\u1ed9t d\u1ea1ng \u0111i\u1ec1u ch\u1ebf bi\u00ean \u0111\u1ed9 xung nh\u1eb1m s\u1eed d\u1ee5ng b\u0103ng th\u00f4ng hi\u1ec7u qu\u1ea3 h\u01a1n. M\u1ed7i k\u00fd hi\u1ec7u trong PAM4 \u0111\u1ea1i di\u1ec7n cho m\u1ed9t c\u1eb7p bit, v\u00ed d\u1ee5 nh\u01b0 00, 01, 10 ho\u1eb7c 11. \u0110i\u1ec1u n\u00e0y gi\u00fap b\u1ea1n g\u1eedi nhi\u1ec1u d\u1eef li\u1ec7u h\u01a1n m\u00e0 kh\u00f4ng c\u1ea7n m\u1edf r\u1ed9ng b\u0103ng th\u00f4ng k\u00eanh.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>B\u1ed1n m\u1ee9c:<\/strong> PAM4 s\u1eed d\u1ee5ng <em>b\u1ed1n<\/em> m\u1ee9c \u0111i\u1ec7n \u00e1p ho\u1eb7c c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng ri\u00eang bi\u1ec7t.<\/p><\/li><li><p style=\"margin: 0px 0px 4px;\"><strong>Hai bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u:<\/strong> M\u1ed7i chu k\u1ef3 k\u00fd hi\u1ec7u gi\u1edd \u0111\u00e2y mang theo <em>hai<\/em> bit th\u00f4ng tin:<\/p><ul><li><p style=\"margin: 0px;\">M\u1ee9c 0: \u201900\u2019<\/p><\/li><li><p style=\"margin: 0px;\">M\u1ee9c 1: \u201901\u2019<\/p><\/li><li><p style=\"margin: 0px;\">M\u1ee9c 2: \u201910\u2019<\/p><\/li><li><p style=\"margin: 0px;\">M\u1ee9c 3: \u201911\u2019<\/p><\/li><\/ul><\/li><li><p style=\"margin: 0px;\"><strong>G\u1ea5p \u0111\u00f4i hi\u1ec7u su\u1ea5t:<\/strong> B\u1eb1ng c\u00e1ch truy\u1ec1n hai bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u, PAM4 \u0111\u1ea1t \u0111\u01b0\u1ee3c t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u g\u1ea5p \u0111\u00f4i so v\u1edbi NRZ <em>\u1edf c\u00f9ng t\u1ed1c \u0111\u1ed9 baud<\/em>. M\u1ed9t t\u00edn hi\u1ec7u PAM4 28 Gigabaud cung c\u1ea5p 56 Gigabit m\u1ed7i gi\u00e2y (Gbps) tr\u00ean m\u1ed7i k\u00eanh, trong khi NRZ ch\u1ec9 cung c\u1ea5p 28 Gbps \u1edf t\u1ed1c \u0111\u1ed9 baud \u0111\u00f3.<\/p><\/li><li><p style=\"margin: 0px 0px 4px;\"><strong>Th\u00e1ch th\u1ee9c:<\/strong> Hi\u1ec7u qu\u1ea3 n\u00e0y \u0111i k\u00e8m v\u1edbi chi ph\u00ed:<\/p><ul><li><p style=\"margin: 0px;\"><strong>Gi\u1ea3m T\u1ef7 s\u1ed1 T\u00edn hi\u1ec7u tr\u00ean Nhi\u1ec5u (SNR):<\/strong> B\u1ed1n m\u1ee9c \u0111i\u1ec7n \u00e1p g\u1ea7n nhau h\u01a1n so v\u1edbi hai m\u1ee9c c\u1ee7a NRZ. \u0110i\u1ec1u n\u00e0y khi\u1ebfn t\u00edn hi\u1ec7u d\u1ec5 b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi nhi\u1ec5u, m\u00e9o d\u1ea1ng v\u00e0 can nhi\u1ec5u h\u01a1n nhi\u1ec1u. \u0110\u1ed9 d\u01b0 th\u1eeba nhi\u1ec5u nh\u1ecf h\u01a1n c\u00f3 th\u1ec3 l\u00e0m thay \u0111\u1ed5i m\u1ee9c v\u00e0 g\u00e2y ra l\u1ed7i.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>\u0110\u1ed9 ph\u1ee9c t\u1ea1p t\u0103ng l\u00ean:<\/strong> PAM4 \u0111\u00f2i h\u1ecfi c\u00e1c thi\u1ebft k\u1ebf b\u1ed9 thu ph\u00e1t tinh vi h\u01a1n \u0111\u00e1ng k\u1ec3, bao g\u1ed3m c\u1ea3 kh\u1ea3 n\u0103ng x\u1eed l\u00fd m\u1ea1nh m\u1ebd <strong>S\u1eeda l\u1ed7i ti\u1ebfn (FEC)<\/strong>, n\u00e2ng cao <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/digital-signal-processor-functionality-in-optical-transceivers\/\"><strong>DSP (X\u1eed l\u00fd t\u00edn hi\u1ec7u s\u1ed1)<\/strong><\/a>, v\u00e0 \u0111\u1ed9 tuy\u1ebfn t\u00ednh ch\u00ednh x\u00e1c trong b\u1ed9 \u0111i\u1ec1u khi\u1ec3n ph\u00e1t v\u00e0 thu. \u0110i\u1ec1u n\u00e0y th\u01b0\u1eddng d\u1eabn \u0111\u1ebfn m\u1ee9c ti\u00eau th\u1ee5 c\u00f4ng su\u1ea5t cao h\u01a1n tr\u00ean m\u1ed7i bit so v\u1edbi c\u00e1c thi\u1ebft k\u1ebf NRZ \u0111\u00e3 tr\u01b0\u1edfng th\u00e0nh.<\/p><\/li><\/ul><\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>L\u01b0u \u00fd: PAM4 c\u00f3 nhi\u1ec1u m\u1ee9c \u0111i\u1ec7n \u00e1p h\u01a1n, do \u0111\u00f3 kho\u1ea3ng c\u00e1ch gi\u1eefa ch\u00fang nh\u1ecf h\u01a1n. \u0110i\u1ec1u n\u00e0y khi\u1ebfn t\u00edn hi\u1ec7u PAM4 d\u1ec5 b\u1ecb nhi\u1ec5u l\u00e0m sai l\u1ec7ch h\u01a1n so v\u1edbi NRZ.<\/p><\/blockquote>\n\n\n\n<h3 class=\"wp-block-heading\" >T\u1ea1i sao \u0111i\u1ec1u ch\u1ebf l\u1ea1i quan tr\u1ecdng<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/what-is-optical-modulation-and-how-it-works-explained\/\"><strong>\u0110i\u1ec1u ch\u1ebf<\/strong><\/a> l\u00e0 c\u1ea7n thi\u1ebft \u0111\u1ec3 truy\u1ec1n d\u1eef li\u1ec7u k\u1ef9 thu\u1eadt s\u1ed1 qua d\u00e2y c\u00e1p ho\u1eb7c s\u1ee3i quang. N\u00f3 thay \u0111\u1ed5i t\u00edn hi\u1ec7u \u0111\u1ec3 t\u00edn hi\u1ec7u c\u00f3 th\u1ec3 truy\u1ec1n \u0111i xa h\u01a1n v\u1edbi \u00edt v\u1ea5n \u0111\u1ec1 h\u01a1n. \u0110\u1ed1i v\u1edbi d\u1eef li\u1ec7u t\u1ed1c \u0111\u1ed9 cao, c\u00e1c c\u00f4ng c\u1ee5 \u0111i\u1ec1u ch\u1ebf b\u00ean ngo\u00e0i\u2014nh\u01b0 b\u1ed9 \u0111i\u1ec1u ch\u1ebf Mach-Zehnder\u2014gi\u00fap duy tr\u00ec \u0111\u1ed9 m\u1ea1nh c\u1ee7a t\u00edn hi\u1ec7u. \u0110i\u1ec1u ch\u1ebf bi\u00ean \u0111\u1ed9 xung (PAM) v\u00e0 c\u00e1c ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c \u0111\u1ec3 thay \u0111\u1ed5i t\u00edn hi\u1ec7u gi\u00fap b\u1ea1n l\u1ef1a ch\u1ecdn s\u1ef1 k\u1ebft h\u1ee3p t\u1ed1i \u01b0u gi\u1eefa t\u1ed1c \u0111\u1ed9, hi\u1ec7u qu\u1ea3 v\u00e0 \u0111\u1ed9 tin c\u1eady.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Bi\u1ec3u \u0111\u1ed3 m\u1eaft v\u00e0 \u0110\u1ed9 to\u00e0n v\u1eb9n t\u00edn hi\u1ec7u<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >Bi\u1ec3u \u0111\u1ed3 m\u1eaft NRZ<\/h3>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1200\" height=\"659\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e.webp\" alt=\"NRZ eye diagram\" class=\"wp-image-5810\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e-300x165.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e-1024x562.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e-768x422.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/e1f1ed087d5b4594a6e4af41382f1e6e-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Khi b\u1ea1n quan s\u00e1t m\u1ed9t <strong>bi\u1ec3u \u0111\u1ed3 m\u1eaft NRZ<\/strong>, b\u1ea1n s\u1ebd th\u1ea5y c\u00e1ch t\u00edn hi\u1ec7u ho\u1ea1t \u0111\u1ed9ng. C\u00f3 hai m\u1ee9c \u0111i\u1ec7n \u00e1p ch\u00ednh, m\u1ed9t cho bit 0 v\u00e0 m\u1ed9t cho bit 1. \u0110i\u1ec1u n\u00e0y t\u1ea1o th\u00e0nh h\u00ecnh d\u1ea1ng \u201cm\u1eaft\u201d r\u1ed9ng m\u1edf trong bi\u1ec3u \u0111\u1ed3. M\u1eaft m\u1edf r\u1ed9ng cho th\u1ea5y t\u00edn hi\u1ec7u m\u1ea1nh v\u00e0 \u00edt b\u1ecb nhi\u1ec5u l\u00e0m sai l\u1ec7ch.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>B\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y hai m\u1ee9c \u0111i\u1ec7n \u00e1p r\u00f5 r\u00e0ng, n\u00ean vi\u1ec7c ph\u00e2n bi\u1ec7t bit 0 v\u00e0 bit 1 r\u1ea5t d\u1ec5 d\u00e0ng.<\/p><\/li><li><p>Ph\u1ea7n m\u1edf r\u1ed9ng ngang c\u1ee7a m\u1eaft cho th\u1ea5y t\u00edn hi\u1ec7u m\u1ea1nh v\u00e0 \u00edt b\u1ecb bi\u1ebfn \u0111\u1ed5i.<\/p><\/li><li><p>C\u00e1c chuy\u1ec3n \u0111\u1ed5i m\u01b0\u1ee3t m\u00e0 gi\u1eefa c\u00e1c m\u1ee9c gi\u00fap b\u1ea1n theo d\u00f5i th\u1eddi \u0111i\u1ec3m ch\u00ednh x\u00e1c h\u01a1n v\u00e0 gi\u1ea3m thi\u1ec3u sai s\u00f3t.<\/p><\/li><li><p>Ph\u1ea7n cao c\u1ee7a m\u1eaft cho bi\u1ebft m\u1ee9c \u0111\u1ed9 nhi\u1ec5u m\u00e0 t\u00edn hi\u1ec7u c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u1ef1ng \u0111\u01b0\u1ee3c.<\/p><\/li><li><p>Ph\u1ea7n r\u1ed9ng c\u1ee7a m\u1eaft cho bi\u1ebft li\u1ec7u c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng rung th\u1eddi gian (jitter) hay nhi\u1ec5u gi\u1eefa c\u00e1c k\u00fd hi\u1ec7u (ISI) hay kh\u00f4ng.<\/p><\/li><li><p>M\u1eaft c\u00e0ng l\u1edbn th\u00ec sai s\u00f3t c\u00e0ng \u00edt v\u00e0 vi\u1ec7c \u0111\u1ed3ng b\u1ed9 th\u1eddi gian c\u00e0ng d\u1ec5 d\u00e0ng.<\/p><\/li><li><p>N\u1ebfu m\u1eaft thu nh\u1ecf l\u1ea1i, \u0111i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 nhi\u1ec5u ho\u1eb7c c\u00e1c v\u1ea5n \u0111\u1ec1 kh\u00e1c \u0111ang l\u00e0m suy gi\u1ea3m t\u00edn hi\u1ec7u.<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c bi\u1ec3u \u0111\u1ed3 m\u1eaft NRZ \u0111\u01a1n gi\u1ea3n v\u00e0 kh\u00f4ng ph\u1ee9c t\u1ea1p b\u1eb1ng PAM4. \u0110i\u1ec1u n\u00e0y khi\u1ebfn NRZ m\u1ea1nh h\u01a1n v\u00e0 d\u1ec5 s\u1eed d\u1ee5ng h\u01a1n khi b\u1ea1n mu\u1ed1n d\u1eef li\u1ec7u c\u1ee7a m\u00ecnh \u0111\u01b0\u1ee3c an to\u00e0n.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Bi\u1ec3u \u0111\u1ed3 m\u1eaft PAM4<\/h3>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1200\" height=\"602\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6.webp\" alt=\" PAM4 eye diagram\" class=\"wp-image-5811\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6-300x151.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6-1024x514.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6-768x385.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/c1f23795d5d84753b9dee268ead913e6-18x9.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>bi\u1ec3u \u0111\u1ed3 m\u1eaft PAM4<\/strong> kh\u00f4ng gi\u1ed1ng v\u1edbi bi\u1ec3u \u0111\u1ed3 m\u1eaft NRZ. B\u1ea1n s\u1ebd th\u1ea5y b\u1ed1n m\u1ee9c \u0111\u1ed9 kh\u00e1c nhau thay v\u00ec ch\u1ec9 hai m\u1ee9c. M\u1ed7i m\u1ee9c \u0111\u1ea1i di\u1ec7n cho m\u1ed9t c\u1eb7p bit hai bit kh\u00e1c nhau. C\u00e1c m\u1ee9c n\u00e0y n\u1eb1m g\u1ea7n nhau, do \u0111\u00f3 c\u00e1c khe m\u1edf m\u1eaft nh\u1ecf h\u01a1n v\u00e0 x\u1ebfp ch\u1ed3ng l\u00ean nhau. \u0110i\u1ec1u n\u00e0y khi\u1ebfn t\u00edn hi\u1ec7u PAM4 d\u1ec5 b\u1ecb nhi\u1ec5u l\u00e0m sai l\u1ec7ch h\u01a1n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng c\u00e1c khe m\u1edf m\u1eaft nh\u1ecf h\u01a1n \u1edf PAM4 ngh\u0129a l\u00e0 n\u00f3 kh\u00f4ng th\u1ec3 ch\u1ecbu \u0111\u1ef1ng \u0111\u01b0\u1ee3c nhi\u1ec1u nhi\u1ec5u nh\u01b0 v\u1eady. Vi\u1ec7c duy tr\u00ec \u0111\u1ed3ng b\u1ed9 th\u1eddi gian tr\u1edf n\u00ean kh\u00f3 kh\u0103n h\u01a1n v\u00ec c\u00e1c khe m\u1edf m\u1eaft kh\u00f4ng l\u1edbn b\u1eb1ng. C\u00e1c khe m\u1edf m\u1eaft x\u1ebfp ch\u1ed3ng c\u00f3 th\u1ec3 h\u00f2a l\u1eabn v\u00e0o nhau n\u1ebfu c\u00f3 qu\u00e1 nhi\u1ec1u nhi\u1ec5u, d\u1eabn \u0111\u1ebfn nhi\u1ec1u l\u1ed7i h\u01a1n. B\u1ea1n c\u1ea7n c\u00e1c c\u00f4ng c\u1ee5 \u0111\u1eb7c bi\u1ec7t \u0111\u1ec3 s\u1eeda l\u1ed7i v\u00e0 gi\u1eef cho t\u00edn hi\u1ec7u PAM4 r\u00f5 r\u00e0ng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Khi so s\u00e1nh c\u1ea3 hai, NRZ cho b\u1ea1n bi\u1ec3u \u0111\u1ed3 m\u1eaft s\u1ea1ch h\u01a1n v\u00e0 l\u1edbn h\u01a1n. PAM4 cho ph\u00e9p b\u1ea1n truy\u1ec1n nhi\u1ec1u d\u1eef li\u1ec7u h\u01a1n, nh\u01b0ng b\u1ea1n ph\u1ea3i theo d\u00f5i t\u00edn hi\u1ec7u k\u1ef9 l\u01b0\u1ee1ng v\u00e0 s\u1eed d\u1ee5ng h\u1ed7 tr\u1ee3 b\u1ed5 sung \u0111\u1ec3 gi\u1eef t\u1ef7 l\u1ec7 l\u1ed7i th\u1ea5p.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Ch\u00fang t\u1ecfa s\u00e1ng \u1edf \u0111\u00e2u? T\u1eadp trung v\u00e0o \u1ee9ng d\u1ee5ng<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>NRZ:<\/strong> V\u1eabn chi\u1ebfm \u01b0u th\u1ebf tuy\u1ec7t \u0111\u1ed1i \u1edf nh\u1eefng n\u01a1i y\u00eau c\u1ea7u t\u00ednh \u0111\u01a1n gi\u1ea3n, hi\u1ec7u qu\u1ea3 n\u0103ng l\u01b0\u1ee3ng v\u00e0 chi ph\u00ed th\u1ea5p cho t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u \u2264 25 Gbps tr\u00ean m\u1ed7i lane. V\u00ed d\u1ee5 nh\u01b0 Ethernet 10 Gigabit (10GbE), Ethernet 25 Gigabit (25GbE) trong k\u1ebft n\u1ed1i m\u00e1y ch\u1ee7 v\u00e0 c\u00e1c h\u1ec7 th\u1ed1ng k\u1ebf th\u1eeba. Nhi\u1ec1u <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\"><strong>b\u1ed9 thu ph\u00e1t quang<\/strong><\/a> lo\u1ea1i nh\u01b0 <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-26192-10g-sfp.htm\"><strong>SFP+<\/strong><\/a> (10G\/25G) v\u00e0 <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-27045-100g-qsfp28-sfp-dd.htm\"><strong>QSFP28<br><\/strong><\/a> (4\u00d725G = 100G) s\u1eed d\u1ee5ng NRZ.<\/p><\/li><li><p style=\"margin: 0px 0px 4px;\"><strong>PAM4:<\/strong> L\u00e0 l\u1ef1a ch\u1ecdn h\u00e0ng \u0111\u1ea7u kh\u00f4ng th\u1ec3 tranh c\u00e3i cho c\u00e1c \u1ee9ng d\u1ee5ng m\u1eadt \u0111\u1ed9 cao, b\u0103ng th\u00f4ng cao \u0111\u00f2i h\u1ecfi 50 Gbps tr\u00ean m\u1ed7i lane tr\u1edf l\u00ean. \u0110\u00e2y l\u00e0 x\u01b0\u01a1ng s\u1ed1ng c\u1ee7a:<\/p><ul><li><p style=\"margin: 0px;\">Ethernet 100 Gigabit (100GbE \u2013 s\u1eed d\u1ee5ng 2 lane PAM4 50G)<\/p><\/li><li><p style=\"margin: 0px;\">Ethernet 200 Gigabit (200GbE \u2013 4\u00d750G PAM4)<\/p><\/li><li><p style=\"margin: 0px;\">Ethernet 400 Gigabit (400GbE \u2013 8\u00d750G PAM4 ho\u1eb7c 4\u00d7100G PAM4)<\/p><\/li><li><p style=\"margin: 0px;\">Ethernet 800 Gigabit (800GbE \u2013 8\u00d7100G PAM4)<\/p><\/li><li><p style=\"margin: 0px;\">C\u00e1c c\u1ee5m tr\u00ed tu\u1ec7 nh\u00e2n t\u1ea1o\/m\u00e1y h\u1ecdc (AI\/ML) v\u00e0 li\u00ean k\u1ebft t\u00ednh to\u00e1n hi\u1ec7u n\u0103ng cao (HPC).<\/p><\/li><\/ul><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 L\u1ef1a ch\u1ecdn gi\u1eefa PAM4 v\u00e0 NRZ<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Khi l\u1ef1a ch\u1ecdn gi\u1eefa PAM4 v\u00e0 NRZ, b\u1ea1n n\u00ean c\u00e2n nh\u1eafc m\u1ed9t v\u00e0i y\u1ebfu t\u1ed1 quan tr\u1ecdng. M\u1ed7i chu\u1ea9n ph\u00f9 h\u1ee3p v\u1edbi nh\u1eefng nhi\u1ec7m v\u1ee5 kh\u00e1c nhau. B\u1ea1n c\u1ea7n ch\u1ecdn chu\u1ea9n ph\u00f9 h\u1ee3p v\u1edbi nhu c\u1ea7u v\u1ec1 t\u1ed1c \u0111\u1ed9, chi ph\u00ed v\u00e0 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng trong t\u01b0\u01a1ng lai c\u1ee7a m\u1ea1ng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 y\u1ebfu t\u1ed1 ch\u00ednh c\u1ea7n c\u00e2n nh\u1eafc:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><strong>Nhu c\u1ea7u t\u1ed1c \u0111\u1ed9<\/strong>: N\u1ebfu m\u1ea1ng c\u1ee7a b\u1ea1n c\u1ea7n t\u1ed1c \u0111\u1ed9 c\u1ef1c cao, v\u00ed d\u1ee5 400G ho\u1eb7c h\u01a1n, PAM4 c\u00f3 th\u1ec3 truy\u1ec1n t\u1ea3i l\u01b0\u1ee3ng d\u1eef li\u1ec7u g\u1ea5p \u0111\u00f4i trong c\u00f9ng m\u1ed9t kh\u00f4ng gian. NRZ ph\u00f9 h\u1ee3p h\u01a1n cho c\u00e1c m\u1ea1ng t\u1ed1c \u0111\u1ed9 th\u1ea5p h\u01a1n, kh\u00f4ng y\u00eau c\u1ea7u nhi\u1ec1u b\u0103ng th\u00f4ng nh\u01b0 v\u1eady.<\/p><\/li><li><p><strong>Ch\u1ea5t l\u01b0\u1ee3ng t\u00edn hi\u1ec7u<\/strong>: NRZ c\u00f3 hai m\u1ee9c \u0111i\u1ec7n \u00e1p n\u00ean ch\u1ed1ng nhi\u1ec5u t\u1ed1t h\u01a1n. B\u1ea1n s\u1ebd g\u1eb7p \u00edt l\u1ed7i h\u01a1n v\u00e0 t\u00edn hi\u1ec7u r\u00f5 r\u00e0ng h\u01a1n. PAM4 c\u00f3 b\u1ed1n m\u1ee9c \u0111i\u1ec7n \u00e1p n\u00ean nhi\u1ec5u d\u1ec5 l\u00e0m sai l\u1ec7ch t\u00edn hi\u1ec7u h\u01a1n. B\u1ea1n s\u1ebd c\u1ea7n c\u00e1c c\u00f4ng c\u1ee5 chuy\u00ean d\u1ee5ng \u0111\u1ec3 s\u1eeda l\u1ed7i v\u1edbi PAM4.<\/p><\/li><li><p><strong>Ph\u1ea7n c\u1ee9ng v\u00e0 Chi ph\u00ed<\/strong>: C\u00e1c linh ki\u1ec7n NRZ \u0111\u01a1n gi\u1ea3n v\u00e0 r\u1ebb ti\u1ec1n h\u01a1n. PAM4 \u0111\u00f2i h\u1ecfi nhi\u1ec1u linh ki\u1ec7n h\u01a1n v\u00e0 chip \u0111\u1eb7c bi\u1ec7t, do \u0111\u00f3 chi ph\u00ed cao h\u01a1n. N\u1ebfu b\u1ea1n mu\u1ed1n ti\u1ebft ki\u1ec7m chi ph\u00ed v\u00e0 gi\u1eef m\u1ecdi th\u1ee9 \u0111\u01a1n gi\u1ea3n, NRZ l\u00e0 l\u1ef1a ch\u1ecdn th\u00f4ng minh.<\/p><\/li><li><p><strong>M\u1ee9c ti\u00eau th\u1ee5 \u0111i\u1ec7n n\u0103ng<\/strong>: NRZ ti\u00eau th\u1ee5 \u00edt n\u0103ng l\u01b0\u1ee3ng h\u01a1n v\u00ec kh\u00f4ng c\u1ea7n x\u1eed l\u00fd b\u1ed5 sung. PAM4 ti\u00eau t\u1ed1n nhi\u1ec1u n\u0103ng l\u01b0\u1ee3ng h\u01a1n \u0111\u1ec3 duy tr\u00ec t\u00edn hi\u1ec7u r\u00f5 r\u00e0ng.<\/p><\/li><li><p><strong>Kho\u1ea3ng c\u00e1ch<\/strong>: NRZ ho\u1ea1t \u0111\u1ed9ng t\u1ed1t h\u01a1n n\u1ebfu b\u1ea1n c\u1ea7n truy\u1ec1n d\u1eef li\u1ec7u \u1edf kho\u1ea3ng c\u00e1ch xa. PAM4 th\u00edch h\u1ee3p nh\u1ea5t cho c\u00e1c k\u1ebft n\u1ed1i ng\u1eafn, v\u00ed d\u1ee5 nh\u01b0 b\u00ean trong trung t\u00e2m d\u1eef li\u1ec7u.<\/p><\/li><li><p><strong>Kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng trong t\u01b0\u01a1ng lai<\/strong>: N\u1ebfu b\u1ea1n mu\u1ed1n n\u00e2ng c\u1ea5p t\u1ed1c \u0111\u1ed9 m\u1ea1ng v\u1ec1 sau, PAM4 c\u00f3 th\u1ec3 \u0111\u00e1p \u1ee9ng c\u00e1c t\u1ed1c \u0111\u1ed9 cao h\u01a1n v\u00e0 c\u00e1c chu\u1ea9n m\u1edbi.<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n c\u00f3 th\u1ec3 th\u1ea5y nh\u1eefng kh\u00e1c bi\u1ec7t n\u00e0y trong b\u1ea3ng d\u01b0\u1edbi \u0111\u00e2y:<\/p>\n\n\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<colgroup><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><\/colgroup><tbody><tr><th colspan=\"1\" rowspan=\"1\"><p>Y\u1ebfu t\u1ed1<br><\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p>\u0110\u1eb7c \u0111i\u1ec3m c\u1ee7a NRZ<\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p>\u0110\u1eb7c \u0111i\u1ec3m c\u1ee7a PAM4<\/p><\/th><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>25Gbps<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>1 bit m\u1ed7i chu k\u1ef3 xung nh\u1ecbp<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>2 bit m\u1ed7i chu k\u1ef3 xung nh\u1ecbp (b\u0103ng th\u00f4ng g\u1ea5p \u0111\u00f4i)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>T\u1ef7 s\u1ed1 t\u00edn hi\u1ec7u tr\u00ean nhi\u1ec5u (SNR)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n, \u00edt nh\u1ea1y c\u1ea3m v\u1edbi nhi\u1ec5u h\u01a1n<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p h\u01a1n, nh\u1ea1y c\u1ea3m v\u1edbi nhi\u1ec5u h\u01a1n<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/understanding-what-is-bit-error-rate\/\"><strong>T\u1ef7 l\u1ec7 l\u1ed7i bit (BER)<\/strong><\/a><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Lower<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n, c\u1ea7n s\u1eeda l\u1ed7i<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>\u0110\u1ed9 ph\u1ee9c t\u1ea1p ph\u1ea7n c\u1ee9ng<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>\u0110\u01a1n gi\u1ea3n, hi\u1ec7u qu\u1ea3 v\u1ec1 chi ph\u00ed<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ph\u1ee9c t\u1ea1p, chi ph\u00ed cao h\u01a1n<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>Ti\u00eau Th\u1ee5 N\u0103ng L\u01b0\u1ee3ng<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Lower<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao h\u01a1n<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>Kho\u1ea3ng c\u00e1ch truy\u1ec1n d\u1eabn<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>D\u00e0i h\u01a1n<br><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ng\u1eafn h\u01a1n<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p>Kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ph\u00f9 h\u1ee3p v\u1edbi nhu c\u1ea7u hi\u1ec7n t\u1ea1i<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>S\u1eb5n s\u00e0ng cho c\u00e1c n\u00e2ng c\u1ea5p trong t\u01b0\u01a1ng lai<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>\ud83d\udca1 <strong>M\u1eb9o:<br><\/strong> Ch\u1ecdn NRZ n\u1ebfu b\u1ea1n mu\u1ed1n gi\u1ea3i ph\u00e1p \u0111\u01a1n gi\u1ea3n v\u00e0 r\u1ebb ti\u1ec1n cho t\u1ed1c \u0111\u1ed9 th\u1ea5p h\u01a1n ho\u1eb7c k\u1ebft n\u1ed1i kho\u1ea3ng c\u00e1ch xa. Ch\u1ecdn PAM4 n\u1ebfu b\u1ea1n c\u1ea7n t\u1ed1c \u0111\u1ed9 nhanh nh\u1ea5t v\u00e0 mu\u1ed1n m\u1ea1ng c\u1ee7a m\u00ecnh c\u00f3 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng trong t\u01b0\u01a1ng lai.<\/p><\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 B\u1ed9 thu ph\u00e1t quang LINK-PP: \u0110\u01b0a hi\u1ec7u n\u0103ng v\u01b0\u1ee3t tr\u1ed9i v\u1edbi \u0111i\u1ec1u ch\u1ebf NRZ v\u00e0 PAM4<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1200\" height=\"675\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630.webp\" alt=\"LINK-PP\" class=\"wp-image-5812\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630-300x169.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630-1024x576.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630-768x432.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/99c1c5c4a1e24fe7ab4c7a9236a91630-18x10.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">L\u1ef1a ch\u1ecdn \u0111\u00fang <strong>b\u1ed9 thu ph\u00e1t quang<\/strong> l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t \u0111\u1ed1i v\u1edbi hi\u1ec7u su\u1ea5t m\u1ea1ng. <strong>LINK-PP<\/strong> cung c\u1ea5p danh m\u1ee5c s\u1ea3n ph\u1ea9m to\u00e0n di\u1ec7n h\u1ed7 tr\u1ee3 c\u1ea3 \u0111i\u1ec1u ch\u1ebf NRZ v\u00e0 PAM4 ti\u00ean ti\u1ebfn:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>\u0110\u1ed1i v\u1edbi \u1ee9ng d\u1ee5ng NRZ:<\/strong> \u0110\u00e1ng tin c\u1eady v\u00e0 hi\u1ec7u qu\u1ea3 v\u1ec1 chi ph\u00ed <strong>b\u1ed9 thu ph\u00e1t quang<\/strong> c\u00e1c gi\u1ea3i ph\u00e1p nh\u01b0 <strong>LINK-PP SFP-25G-SR <\/strong><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/473141.htm\"><strong>LS-MM8525-S1C<\/strong><\/a> or <strong>LI\u00caN K\u1ebeT-PP QSFP28-100G-SR4<\/strong> <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/473115.htm\"><strong>LQ-M85100-SR4C<\/strong><\/a> mang l\u1ea1i hi\u1ec7u n\u0103ng NRZ \u1ed5n \u0111\u1ecbnh 25G m\u1ed7i lane cho c\u00e1c tri\u1ec3n khai 10G, 25G v\u00e0 100G (4\u00d725G).<\/p><\/li><li><p style=\"margin: 0px 0px 4px;\"><strong>\u0110\u1ed1i v\u1edbi \u1ee9ng d\u1ee5ng PAM4 t\u1ed1c \u0111\u1ed9 cao:<\/strong> C\u00e1c b\u1ed9 thu ph\u00e1t PAM4 ti\u00ean ti\u1ebfn c\u1ee7a ch\u00fang t\u00f4i <strong>b\u1ed9 thu ph\u00e1t quang<\/strong> m\u00f4-\u0111un \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 v\u01b0\u1ee3t qua c\u00e1c th\u00e1ch th\u1ee9c v\u1ec1 \u0111\u1ed9 to\u00e0n v\u1eb9n t\u00edn hi\u1ec7u:<\/p><ul><li><p style=\"margin: 0px;\"><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/470377.htm\"><strong>LINK-PP LQD-CW400-DR4C:<\/strong><\/a> L\u00fd t\u01b0\u1edfng cho s\u1ee3i quang \u0111\u01a1n mode c\u1ef1 ly ng\u1eafn 400G s\u1eed d\u1ee5ng PAM4 4\u00d7100G.<\/p><\/li><\/ul><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Nh\u1eefng <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\"><strong>module thu ph\u00e1t quang LINK-PP<\/strong><\/a> t\u00edch h\u1ee3p b\u1ed9 x\u1eed l\u00fd t\u00edn hi\u1ec7u s\u1ed1 (DSP) tinh vi v\u00e0 m\u00e3 h\u00f3a s\u1eeda l\u1ed7i m\u1ea1nh (FEC) nh\u1eb1m \u0111\u1ea3m b\u1ea3o k\u1ebft n\u1ed1i \u0111\u00e1ng tin c\u1eady, hi\u1ec7u n\u0103ng cao trong c\u00e1c m\u00f4i tr\u01b0\u1eddng PAM4 \u0111\u00f2i h\u1ecfi kh\u1eaft khe, khi\u1ebfn ch\u00fang tr\u1edf th\u00e0nh y\u1ebfu t\u1ed1 thi\u1ebft y\u1ebfu cho c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng trung t\u00e2m d\u1eef li\u1ec7u v\u00e0 tr\u00ed tu\u1ec7 nh\u00e2n t\u1ea1o (AI) th\u1ebf h\u1ec7 ti\u1ebfp theo.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 T\u01b0\u01a1ng lai thu\u1ed9c v\u1ec1 c\u00e1c s\u01a1 \u0111\u1ed3 \u0111i\u1ec1u ch\u1ebf \u0111a m\u1ee9c<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">M\u1eb7c d\u00f9 NRZ v\u1eabn gi\u1eef vai tr\u00f2 then ch\u1ed1t, xu h\u01b0\u1edbng ph\u00e1t tri\u1ec3n c\u1ee7a m\u1ea1ng t\u1ed1c \u0111\u1ed9 cao r\u00f5 r\u00e0ng \u0111ang h\u01b0\u1edbng t\u1edbi PAM4 v\u00e0 c\u00f3 th\u1ec3 l\u00e0 c\u1ea3 nh\u1eefng s\u01a1 \u0111\u1ed3 \u0111i\u1ec1u ch\u1ebf ph\u1ee9c t\u1ea1p h\u01a1n n\u1eefa (nh\u01b0 PAM8 ho\u1eb7c PAM16) khi ch\u00fang ta ti\u1ebfn t\u1edbi chu\u1ea9n Ethernet 1,6 Terabit v\u00e0 xa h\u01a1n. Kh\u1ea3 n\u0103ng c\u1ee7a PAM4 trong vi\u1ec7c nh\u00e2n \u0111\u00f4i t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u m\u00e0 kh\u00f4ng c\u1ea7n nh\u00e2n \u0111\u00f4i t\u1ed1c \u0111\u1ed9 baud l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t \u0111\u1ec3 khai th\u00e1c t\u1ed1i \u0111a c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng s\u1ee3i quang hi\u1ec7n c\u00f3. Vi\u1ec7c tri\u1ec3n khai th\u00e0nh c\u00f4ng PAM4 ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c th\u00e0nh ph\u1ea7n ch\u1ea5t l\u01b0\u1ee3ng cao v\u00e0 thi\u1ebft k\u1ebf tinh vi\u2014ch\u00ednh x\u00e1c l\u00e0 l\u0129nh v\u1ef1c m\u00e0 nh\u1eefng nh\u00e0 \u0111\u1ed5i m\u1edbi nh\u01b0 LINK-PP n\u1ed5i b\u1eadt. <strong>b\u1ed9 thu ph\u00e1t quang<\/strong> thi\u1ebft k\u1ebf \u2013 \u0111\u00fang n\u01a1i m\u00e0 nh\u1eefng nh\u00e0 \u0111\u1ed5i m\u1edbi nh\u01b0 LINK-PP t\u1ecfa s\u00e1ng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>S\u1eb5n s\u00e0ng t\u1ed1i \u01b0u h\u00f3a m\u1ea1ng t\u1ed1c \u0111\u1ed9 cao c\u1ee7a b\u1ea1n?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Vi\u1ec7c hi\u1ec3u r\u00f5 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa NRZ v\u00e0 PAM4 l\u00e0 n\u1ec1n t\u1ea3ng thi\u1ebft y\u1ebfu \u0111\u1ec3 thi\u1ebft k\u1ebf v\u00e0 qu\u1ea3n l\u00fd c\u00e1c m\u1ea1ng hi\u1ec7n \u0111\u1ea1i, b\u0103ng th\u00f4ng cao. D\u00f9 b\u1ea1n \u0111ang n\u00e2ng c\u1ea5p c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng c\u0169 hay tri\u1ec3n khai c\u00e1c c\u1ee5m AI ti\u00ean ti\u1ebfn nh\u1ea5t, vi\u1ec7c l\u1ef1a ch\u1ecdn s\u01a1 \u0111\u1ed3 \u0111i\u1ec1u ch\u1ebf ph\u00f9 h\u1ee3p v\u00e0 \u0111\u1ed1i t\u00e1c \u0111\u00fang \u0111\u1eafn \u0111\u1ec1u mang t\u00ednh quy\u1ebft \u0111\u1ecbnh. <strong>b\u1ed9 thu ph\u00e1t quang<\/strong> \u0111\u1ed1i t\u00e1c l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t.<\/p>\n\n\n\n<div><div widgetid=\"3ef779ac451211f099380a58fbc66727\" format=\"embedded\" data-widget-id=\"3ef779ac451211f099380a58fbc66727\" data-mode=\"production.zh\" style=\"display: block;\"><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>FAQ<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110i\u1ec1u g\u00ec khi\u1ebfn PAM4 v\u01b0\u1ee3t tr\u1ed9i h\u01a1n NRZ trong truy\u1ec1n d\u1eef li\u1ec7u t\u1ed1c \u0111\u1ed9 cao?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n \u0111\u1ea1t \u0111\u01b0\u1ee3c t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u g\u1ea5p \u0111\u00f4i v\u1edbi PAM4 v\u00ec n\u00f3 truy\u1ec1n hai bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u. Trong khi \u0111\u00f3, NRZ ch\u1ec9 truy\u1ec1n m\u1ed9t bit tr\u00ean m\u1ed7i k\u00fd hi\u1ec7u. PAM4 ho\u1ea1t \u0111\u1ed9ng t\u1ed1t nh\u1ea5t khi b\u1ea1n c\u1ea7n t\u0103ng t\u1ed1c \u0111\u1ed9 m\u1ea1ng.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Li\u1ec7u PAM4 lu\u00f4n ti\u00eau th\u1ee5 nhi\u1ec1u \u0111i\u1ec7n n\u0103ng h\u01a1n NRZ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">PAM4 th\u01b0\u1eddng ti\u00eau t\u1ed1n nhi\u1ec1u \u0111i\u1ec7n n\u0103ng h\u01a1n. B\u1ea1n ph\u1ea3i s\u1eed d\u1ee5ng th\u00eam c\u00e1c m\u1ea1ch \u0111i\u1ec7n \u0111\u1ec3 th\u1ef1c hi\u1ec7n ch\u1ee9c n\u0103ng s\u1eeda l\u1ed7i v\u00e0 x\u1eed l\u00fd t\u00edn hi\u1ec7u. NRZ ti\u00eau th\u1ee5 \u00edt \u0111i\u1ec7n n\u0103ng h\u01a1n do thi\u1ebft k\u1ebf \u0111\u01a1n gi\u1ea3n h\u01a1n.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Vi\u1ec7c l\u1eafp \u0111\u1eb7t PAM4 hay NRZ d\u1ec5 d\u00e0ng h\u01a1n?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n s\u1ebd th\u1ea5y NRZ d\u1ec5 l\u1eafp \u0111\u1eb7t h\u01a1n. N\u00f3 s\u1eed d\u1ee5ng ph\u1ea7n c\u1ee9ng \u0111\u01a1n gi\u1ea3n v\u00e0 y\u00eau c\u1ea7u \u00edt \u0111i\u1ec1u ch\u1ec9nh h\u01a1n. PAM4 \u0111\u00f2i h\u1ecfi quy tr\u00ecnh thi\u1ebft l\u1eadp ph\u1ee9c t\u1ea1p h\u01a1n v\u00e0 thi\u1ebft k\u1ebf c\u1ea9n tr\u1ecdng \u0111\u1ec3 x\u1eed l\u00fd nhi\u1ec5u v\u00e0 l\u1ed7i.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >B\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u1ed3ng th\u1eddi PAM4 v\u00e0 NRZ trong c\u00f9ng m\u1ed9t m\u1ea1ng kh\u00f4ng?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f3, b\u1ea1n ho\u00e0n to\u00e0n c\u00f3 th\u1ec3 k\u1ebft h\u1ee3p c\u1ea3 hai. B\u1ea1n d\u00f9ng NRZ cho c\u00e1c li\u00ean k\u1ebft c\u0169 h\u01a1n ho\u1eb7c li\u00ean k\u1ebft d\u00e0i h\u01a1n, c\u00f2n d\u00f9ng PAM4 cho c\u00e1c k\u1ebft n\u1ed1i m\u1edbi, t\u1ed1c \u0111\u1ed9 cao. \u0110i\u1ec1u n\u00e0y gi\u00fap b\u1ea1n n\u00e2ng c\u1ea5p m\u1ea1ng t\u1eebng b\u01b0\u1edbc m\u1ed9t.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110\u1ed1i v\u1edbi kho\u1ea3ng c\u00e1ch truy\u1ec1n d\u00e0i, PAM4 hay NRZ t\u1ed1t h\u01a1n?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">NRZ ho\u1ea1t \u0111\u1ed9ng t\u1ed1t h\u01a1n \u1edf kho\u1ea3ng c\u00e1ch truy\u1ec1n d\u00e0i. N\u00f3 x\u1eed l\u00fd nhi\u1ec5u hi\u1ec7u qu\u1ea3 v\u00e0 duy tr\u00ec t\u00edn hi\u1ec7u r\u00f5 r\u00e0ng. PAM4 ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c li\u00ean k\u1ebft ng\u1eafn \u0111\u1ebfn trung b\u00ecnh, n\u01a1i b\u1ea1n c\u1ea7n t\u1ed1c \u0111\u1ed9 cao h\u01a1n.<\/p>\n\n\n\n<script src=\"https:\/\/cdn.mylandingpages.co\/widgets\/platform\/platform.widget.js\" async=\"true\"><\/script>","protected":false},"excerpt":{"rendered":"<p>PAM4 so v\u1edbi NRZ: So s\u00e1nh t\u1ed1c \u0111\u1ed9 d\u1eef li\u1ec7u, kh\u1ea3 n\u0103ng ch\u1ecbu nhi\u1ec5u v\u00e0 hi\u1ec7u su\u1ea5t \u0111\u1ec3 ch\u1ecdn ph\u01b0\u01a1ng th\u1ee9c \u0111i\u1ec1u ch\u1ebf t\u1ed1t nh\u1ea5t cho vi\u1ec7c n\u00e2ng c\u1ea5p m\u1ea1ng v\u00e0 trung t\u00e2m d\u1eef li\u1ec7u c\u1ee7a b\u1ea1n.<\/p>","protected":false},"author":1,"featured_media":5807,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[26],"class_list":["post-5813","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledge-center","tag-optics-transceivers"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/5813","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/comments?post=5813"}],"version-history":[{"count":4,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/5813\/revisions"}],"predecessor-version":[{"id":11381,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/5813\/revisions\/11381"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media\/5807"}],"wp:attachment":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media?parent=5813"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/categories?post=5813"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/tags?post=5813"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}