{"id":3578,"date":"2025-11-28T00:00:00","date_gmt":"2025-11-28T00:00:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/glossary\/what-is-physical-medium-dependent-pmd\/"},"modified":"2026-06-22T04:35:06","modified_gmt":"2026-06-22T04:35:06","slug":"what-is-physical-medium-dependent-pmd","status":"publish","type":"post","link":"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/what-is-physical-medium-dependent-pmd","title":{"rendered":"H\u01b0\u1edbng d\u1eabn th\u1ef1c t\u1ebf v\u1ec1 PMD (Ph\u1ee5 thu\u1ed9c v\u00e0o m\u00f4i tr\u01b0\u1eddng v\u1eadt l\u00fd) cho c\u00e1c li\u00ean k\u1ebft quang"},"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\/0cd5f86bb90c45a09b502f640fbf4abe.webp\" alt=\"PMD (Physical Medium Dependent)\" class=\"wp-image-3574\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/0cd5f86bb90c45a09b502f640fbf4abe.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/0cd5f86bb90c45a09b502f640fbf4abe-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/0cd5f86bb90c45a09b502f640fbf4abe-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/0cd5f86bb90c45a09b502f640fbf4abe-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/0cd5f86bb90c45a09b502f640fbf4abe-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>Ph\u1ee5 thu\u1ed9c v\u00e0o ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd (PMD)<\/strong> l\u1edbp con l\u00e0 m\u1ed9t trong nh\u1eefng th\u00e0nh ph\u1ea7n quan tr\u1ecdng nh\u1ea5t c\u1ee7a t\u1ea7ng v\u1eadt l\u00fd Ethernet, th\u1ebf nh\u01b0ng n\u00f3 th\u01b0\u1eddng b\u1ecb hi\u1ec3u sai. PMD \u0111\u1ecbnh ngh\u0129a c\u00e1ch c\u00e1c bit \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0 nh\u1eadn v\u1eadt l\u00fd tr\u00ean m\u1ed9t ph\u01b0\u01a1ng ti\u1ec7n c\u1ee5 th\u1ec3\u2014s\u1ee3i quang \u0111\u01a1n mode, s\u1ee3i quang \u0111a mode, c\u00e1p \u0111\u1ed3ng g\u1eafn tr\u1ef1c ti\u1ebfp ho\u1eb7c m\u1eb7t ph\u1eb3ng \u0111i\u1ec7n t\u1eed ph\u00eda sau.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi c\u00e1c nh\u00e0 thi\u1ebft k\u1ebf m\u1ea1ng, k\u1ef9 s\u01b0 ki\u1ec3m th\u1eed v\u00e0 \u0111\u1ed9i ng\u0169 mua s\u1eafm, vi\u1ec7c hi\u1ec3u r\u00f5 PMD l\u00e0 \u0111i\u1ec1u thi\u1ebft y\u1ebfu v\u00ec c\u00e1c \u0111\u1eb7c t\u1ea3 PMD \u1ea3nh h\u01b0\u1edfng tr\u1ef1c ti\u1ebfp \u0111\u1ebfn <strong>kh\u1ea3 n\u0103ng t\u01b0\u01a1ng t\u00e1c<\/strong>, <strong>reach<\/strong>, <strong>\u0111\u1ed9 to\u00e0n v\u1eb9n t\u00edn hi\u1ec7u<\/strong>, and <strong>vi\u1ec7c l\u1ef1a ch\u1ecdn b\u1ed9 thu ph\u00e1t<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">H\u01b0\u1edbng d\u1eabn n\u00e0y cung c\u1ea5p gi\u1ea3i th\u00edch chuy\u00ean nghi\u1ec7p, ph\u00f9 h\u1ee3p v\u1edbi ti\u00eau chu\u1ea9n v\u1ec1 PMD, bao g\u1ed3m c\u00e1c th\u00f4ng s\u1ed1 b\u1ea1n ph\u1ea3i \u0111\u00e1nh gi\u00e1 khi l\u1ef1a ch\u1ecdn <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\">b\u1ed9 thu ph\u00e1t quang<\/a> ch\u1eb3ng h\u1ea1n nh\u01b0 c\u00e1c module SFP, SFP+ v\u00e0 QSFP.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f L\u1edbp con Ph\u1ee5 thu\u1ed9c v\u00e0o ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd (PMD) l\u00e0 g\u00ec?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>Ph\u1ee5 thu\u1ed9c v\u00e0o ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd (PMD)<\/strong> l\u1edbp con l\u00e0 kh\u1ed1i ch\u1ee9c n\u0103ng th\u1ea5p nh\u1ea5t c\u1ee7a <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/ieee-802-3-ethernet-standard-explained\/\">IEEE 802.3<\/a> PHY. N\u00f3 \u0111\u1ecbnh ngh\u0129a c\u00e1c <strong>\u0111\u1eb7c t\u00ednh quang h\u1ecdc ho\u1eb7c \u0111i\u1ec7n<\/strong> c\u1ea7n thi\u1ebft \u0111\u1ec3 truy\u1ec1n d\u1eabn th\u00e0nh c\u00f4ng tr\u00ean ph\u01b0\u01a1ng ti\u1ec7n \u0111\u00e3 ch\u1ecdn.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong s\u1ea3n ph\u1ea9m th\u1ef1c t\u1ebf, PMD t\u01b0\u01a1ng \u1ee9ng v\u1edbi giao di\u1ec7n \u0111\u1ea7u cu\u1ed1i c\u1ee7a b\u1ed9 thu ph\u00e1t quang\u2014bao g\u1ed3m laser, \u0111i\u1ed1t quang thu, m\u1ea1ch \u0111i\u1ec1u ch\u1ebf v\u00e0 c\u00e1c th\u00e0nh ph\u1ea7n li\u00ean quan.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Nh\u1eefng y\u1ebfu t\u1ed1 do PMD ki\u1ec3m so\u00e1t<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>b\u01b0\u1edbc s\u00f3ng quang v\u00e0 \u0111\u1ed9 r\u1ed9ng ph\u1ed5<\/p><\/li><li><p>c\u00f4ng su\u1ea5t trung b\u00ecnh ph\u00e1t (Tx) v\u00e0 \u0111i\u1ec1u ki\u1ec7n ph\u00e1t<\/p><\/li><li><p>\u0111\u1ed9 nh\u1ea1y thu (Rx) v\u00e0 gi\u1edbi h\u1ea1n qu\u00e1 t\u1ea3i<\/p><\/li><li><p>Quang h\u1ecdc <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/optical-transceiver-return-loss-back-reflection-guide\/\">t\u1ed5n hao ph\u1ea3n h\u1ed3i<\/a> v\u00e0 t\u1ef7 s\u1ed1 t\u1eaft m\u1edf (extinction ratio)<\/p><\/li><li><p>lo\u1ea1i s\u1ee3i quang \u0111\u01b0\u1ee3c h\u1ed7 tr\u1ee3 v\u00e0 kho\u1ea3ng c\u00e1ch \u0111\u01b0\u1eddng truy\u1ec1n<\/p><\/li><li><p>m\u1eb7t n\u1ea1 m\u1eaft (eye masks) \u0111i\u1ec7n cho vi\u1ec7c truy\u1ec1n\/thu (\u0111\u1ed1i v\u1edbi PHY \u0111i\u1ec7n)<\/p><\/li><li><p>\u0111\u1ecbnh ngh\u0129a \u0111i\u1ec3m ki\u1ec3m tra \u0111\u1ec3 \u0111o l\u01b0\u1eddng tu\u00e2n th\u1ee7<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">PMD \u0111\u00f3ng vai tr\u00f2 l\u00e0 <strong>c\u1ea7u n\u1ed1i gi\u1eefa logic PHY \u0111\u01b0\u1ee3c chu\u1ea9n h\u00f3a v\u00e0 th\u1ebf gi\u1edbi v\u1eadt l\u00fd<\/strong>, \u0111\u1ea3m b\u1ea3o c\u00e1c b\u1ed9 thu ph\u00e1t t\u1eeb nhi\u1ec1u nh\u00e0 cung c\u1ea5p kh\u00e1c nhau c\u00f3 th\u1ec3 ho\u1ea1t \u0111\u1ed9ng t\u01b0\u01a1ng th\u00edch tr\u00ean c\u00f9ng m\u1ed9t h\u1ec7 th\u1ed1ng s\u1ee3i quang.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f PMD so v\u1edbi c\u00e1c l\u1edbp con PHY kh\u00e1c<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Ki\u1ebfn tr\u00fac PHY Ethernet th\u01b0\u1eddng bao g\u1ed3m:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/pcs-physical-coding-sublayer-ethernet-explained\/\"><strong>PCS (L\u1edbp m\u00e3 h\u00f3a v\u1eadt l\u00fd)<\/strong> <\/a>\u2014 m\u00e3 h\u00f3a, 64b\/66b, <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/fec-forward-error-correction-in-optical-communication\/\">FEC<\/a>, v\u00e0 ph\u00e2n ph\u1ed1i k\u00eanh<\/p><\/li><li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/pma-physical-medium-attachment-ethernet-explained\/\"><strong>PMA (B\u1ed9 g\u1eafn ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd)<\/strong><\/a> \u2014 tu\u1ea7n t\u1ef1 h\u00f3a\/gi\u1ea3i tu\u1ea7n t\u1ef1 h\u00f3a, kh\u00f4i ph\u1ee5c \u0111\u1ed3ng h\u1ed3<\/p><\/li><li><p><strong>PMD (Ph\u1ee5 thu\u1ed9c v\u00e0o ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd)<\/strong> \u2014 c\u00e1c th\u00f4ng s\u1ed1 quang h\u1ecdc\/\u0111i\u1ec7n \u0111\u1eb7c th\u00f9 cho ph\u01b0\u01a1ng ti\u1ec7n<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">PMD l\u00e0 ph\u1ea7n tr\u1ef1c ti\u1ebfp li\u00ean quan \u0111\u1ebfn ng\u00e2n s\u00e1ch quang v\u00e0 lo\u1ea1i ph\u01b0\u01a1ng ti\u1ec7n.<br\/>M\u1ed9t MAC duy nh\u1ea5t c\u00f3 th\u1ec3 h\u1ed7 tr\u1ee3 nhi\u1ec1u PMD (v\u00ed d\u1ee5: SR, LR, ER), m\u1ed7i PMD \u0111\u01b0\u1ee3c t\u1ed1i \u01b0u h\u00f3a cho t\u1ea7m xa ho\u1eb7c ph\u01b0\u01a1ng ti\u1ec7n kh\u00e1c nhau.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f V\u00ec sao PMD quan tr\u1ecdng trong c\u00e1c m\u1ea1ng th\u1ef1c t\u1ebf<\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34.webp\" alt=\"Why PMD Matters in Real Networks\" class=\"wp-image-3575\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/27e048578ea044bf9f40c798076a3c34-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110\u1ea3m b\u1ea3o kh\u1ea3 n\u0103ng t\u01b0\u01a1ng t\u00e1c (interoperability)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ch\u1ec9 c\u00e1c m\u00f4-\u0111un tu\u00e2n th\u1ee7 c\u00f9ng m\u1ed9t th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt PMD m\u1edbi c\u00f3 th\u1ec3 k\u1ebft n\u1ed1i \u0111\u00e1ng tin c\u1eady v\u1edbi nhau. B\u01b0\u1edbc s\u00f3ng, m\u1ee9c c\u00f4ng su\u1ea5t v\u00e0 \u0111\u1ed9 nh\u1ea1y ph\u1ea3i ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c y\u00eau c\u1ea7u c\u1ee7a IEEE.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Ph\u1ea1m vi k\u1ebft n\u1ed1i d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c th\u00f4ng s\u1ed1 PMD x\u00e1c \u0111\u1ecbnh ng\u00e2n s\u00e1ch t\u1ed5n hao li\u00ean k\u1ebft. N\u1ebfu m\u1ed9t m\u00f4-\u0111un quy \u0111\u1ecbnh c\u00f4ng su\u1ea5t ph\u00e1t (Tx) t\u1eeb \u20133 dBm \u0111\u1ebfn +3 dBm v\u00e0 \u0111\u1ed9 nh\u1ea1y thu (Rx) l\u00e0 \u201314 dBm, th\u00ec ng\u00e2n s\u00e1ch quang h\u1ecdc s\u1eed d\u1ee5ng \u0111\u01b0\u1ee3c s\u1ebd \u0111\u01b0\u1ee3c t\u00ednh t\u1eeb c\u00e1c gi\u00e1 tr\u1ecb n\u00e0y.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Ki\u1ec3m tra v\u00e0 tu\u00e2n th\u1ee7 ch\u00ednh x\u00e1c<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">PMD x\u00e1c \u0111\u1ecbnh c\u00e1c \u0111i\u1ec3m ki\u1ec3m tra ti\u00eau chu\u1ea9n (v\u00ed d\u1ee5: TP2, TP3), \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00f4ng su\u1ea5t quang, \u0111\u1ed9 ch\u1eadp ch\u1eddn (jitter) v\u00e0 bi\u1ec3u \u0111\u1ed3 m\u1eaft (eye diagrams) \u0111\u01b0\u1ee3c \u0111o m\u1ed9t c\u00e1ch nh\u1ea5t qu\u00e1n.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110\u1ed9 tin c\u1eady theo th\u1eddi gian<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c m\u00f4-\u0111un c\u00f3 bi\u00ean d\u1ef1 ph\u00f2ng PMD l\u1edbn h\u01a1n ch\u1ecbu \u0111\u1ef1ng t\u1ed1t h\u01a1n hi\u1ec7n t\u01b0\u1ee3ng l\u00e3o h\u00f3a, bi\u1ebfn thi\u00ean nhi\u1ec7t \u0111\u1ed9, nhi\u1ec5m b\u1ea9n s\u1ee3i quang v\u00e0 ph\u1ea3n x\u1ea1 t\u1ea1i \u0111\u1ea7u n\u1ed1i so v\u1edbi c\u00e1c m\u00f4-\u0111un ch\u1ec9 \u0111\u00e1p \u1ee9ng m\u1ee9c t\u1ed1i thi\u1ec3u.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f C\u00e1c th\u00f4ng s\u1ed1 PMD then ch\u1ed1t b\u1ea1n ph\u1ea3i \u0111\u00e1nh gi\u00e1<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">M\u1ed7i th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt PMD bao g\u1ed3m nhi\u1ec1u th\u00f4ng s\u1ed1 quang h\u1ecdc v\u00e0 \u0111i\u1ec7n h\u1ecdc quan tr\u1ecdng. Vi\u1ec7c hi\u1ec3u r\u00f5 ch\u00fang gi\u00fap \u0111\u1ea3m b\u1ea3o l\u1ef1a ch\u1ecdn m\u00f4-\u0111un ph\u00f9 h\u1ee3p.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >B\u01b0\u1edbc s\u00f3ng (\u03bb) v\u00e0 \u0111\u1ed9 r\u1ed9ng ph\u1ed5<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c gi\u00e1 tr\u1ecb ph\u1ed5 bi\u1ebfn bao g\u1ed3m:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/850nm-optical-transceivers-for-short-reach-mmf-transmission\/\"><strong>850nm<\/strong><\/a> \u2014 \u0111a mode t\u1ea7m ng\u1eafn (SR)<\/p><\/li><li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/1310nm-optical-module-applications-performance-comparison\/\"><strong>1310nm<\/strong><\/a> \u2014 \u0111\u01a1n mode t\u1ea7m trung (LR)<\/p><\/li><li><p>C\u00e1c d\u1ea3i c\u1ee5 th\u1ec3 cho c\u00e1c bi\u1ebfn th\u1ec3 LX, BX, CWDM v\u00e0 DWDM<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed9 r\u1ed9ng ph\u1ed5 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u n\u0103ng t\u00e1n s\u1eafc, \u0111\u1eb7c bi\u1ec7t \u0111\u1ed1i v\u1edbi c\u00e1c li\u00ean k\u1ebft t\u1ea7m xa.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >C\u00f4ng su\u1ea5t trung b\u00ecnh b\u1ed9 ph\u00e1t (Tx)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Quy \u0111\u1ecbnh c\u00f4ng su\u1ea5t \u0111\u1ea7u ra t\u1ed1i thi\u1ec3u v\u00e0 t\u1ed1i \u0111a.<br\/>Qu\u00e1 th\u1ea5p \u2192 li\u00ean k\u1ebft c\u00f3 th\u1ec3 kh\u00f4ng t\u1edbi \u0111\u01b0\u1ee3c b\u1ed9 thu.<br\/>Qu\u00e1 cao \u2192 c\u00f3 th\u1ec3 l\u00e0m qu\u00e1 t\u1ea3i b\u1ed9 thu ho\u1eb7c g\u00e2y hi\u1ec7u \u1ee9ng phi tuy\u1ebfn.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110\u1ed9 nh\u1ea1y v\u00e0 ng\u01b0\u1ee1ng qu\u00e1 t\u1ea3i c\u1ee7a b\u1ed9 thu<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><strong>\u0110\u1ed9 nh\u1ea1y:<\/strong> m\u1ee9c c\u00f4ng su\u1ea5t th\u1ea5p nh\u1ea5t m\u00e0 b\u1ed9 thu v\u1eabn \u0111\u00e1p \u1ee9ng \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u BER<\/p><\/li><li><p><strong>Ng\u01b0\u1ee1ng qu\u00e1 t\u1ea3i:<\/strong> m\u1ee9c c\u00f4ng su\u1ea5t \u0111\u1ea7u v\u00e0o t\u1ed1i \u0111a tr\u01b0\u1edbc khi x\u1ea3y ra m\u00e9o t\u00edn hi\u1ec7u<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Hai gi\u00e1 tr\u1ecb n\u00e0y x\u00e1c \u0111\u1ecbnh ph\u1ea1m vi s\u1eed d\u1ee5ng \u0111\u01b0\u1ee3c <strong>ng\u00e2n s\u00e1ch c\u00f4ng su\u1ea5t quang<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >T\u1ef7 s\u1ed1 t\u1eaft s\u00e1ng (Extinction Ratio) v\u00e0 t\u1ed5n hao ph\u1ea3n x\u1ea1 quang (Return Loss)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/extinction-ratio-importance-signal-quality-data-reliability\/\"><strong>T\u1ef7 s\u1ed1 t\u1eaft<\/strong><\/a> \u0111\u1ea3m b\u1ea3o s\u1ef1 ph\u00e2n bi\u1ec7t r\u00f5 r\u00e0ng gi\u1eefa tr\u1ea1ng th\u00e1i logic \u201c1\u201d v\u00e0 \u201c0\u201d.\u201d<\/p><\/li><li><p><strong>T\u1ed5n hao ph\u1ea3n x\u1ea1 quang (Optical return loss)<\/strong> x\u00e1c \u0111\u1ecbnh kh\u1ea3 n\u0103ng ch\u1ecbu \u0111\u1ef1ng ph\u1ea3n x\u1ea1\u2014\u0111\u1eb7c bi\u1ec7t quan tr\u1ecdng tr\u00ean c\u00e1c \u0111o\u1ea1n s\u1ee3i \u0111\u01a1n mode d\u00e0i.<\/p><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" >Lo\u1ea1i s\u1ee3i quang h\u1ed7 tr\u1ee3 v\u00e0 t\u1ea7m xa<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c b\u1ea3ng PMD quy \u0111\u1ecbnh:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>T\u1ea7m xa tr\u00ean s\u1ee3i \u0111a mode OM2\/OM3\/OM4<\/p><\/li><li><p>T\u1ea7m xa tr\u00ean s\u1ee3i \u0111\u01a1n mode G.652\/G.655<\/p><\/li><li><p>Chi\u1ec1u d\u00e0i t\u1ed1i \u0111a \u0111\u01b0\u1ee3c h\u1ed7 tr\u1ee3 theo ng\u00e2n s\u00e1ch c\u00f4ng su\u1ea5t c\u1ee7a IEEE<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f Vai tr\u00f2 c\u1ee7a PMD trong vi\u1ec7c l\u1ef1a ch\u1ecdn b\u1ed9 thu ph\u00e1t quang<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Khi l\u1ef1a ch\u1ecdn m\u00f4-\u0111un quang cho <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/what-is-a-data-center\/\">trung t\u00e2m d\u1eef li\u1ec7u<br><\/a>, m\u1ea1ng c\u00f4ng nghi\u1ec7p ho\u1eb7c c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng vi\u1ec5n th\u00f4ng, vi\u1ec7c x\u00e1c nh\u1eadn s\u1ef1 tu\u00e2n th\u1ee7 PMD \u0111\u1ea3m b\u1ea3o:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>T\u01b0\u01a1ng th\u00edch chu\u1ea9n IEEE th\u1ef1c t\u1ebf<\/p><\/li><li><p>Ph\u1ea1m vi truy\u1ec1n d\u1eabn ch\u00ednh x\u00e1c tr\u00ean s\u1ee3i quang hi\u1ec7n c\u00f3<\/p><\/li><li><p>Bi\u00ean d\u1ef1 ph\u00f2ng suy hao c\u00f3 th\u1ec3 d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c<\/p><\/li><li><p>Hi\u1ec7u n\u0103ng \u1ed5n \u0111\u1ecbnh trong m\u00f4i tr\u01b0\u1eddng ch\u1ecbu \u1ee9ng su\u1ea5t nhi\u1ec7t ho\u1eb7c nhi\u1ec5u<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">V\u00ed d\u1ee5, vi\u1ec7c l\u1ef1a ch\u1ecdn gi\u1eefa <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/475415.htm\"><strong>10GBASE-SR<\/strong><\/a>, <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/475586.htm\"><strong>10GBASE-LR<\/strong><\/a>, and <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/476054.htm\"><strong>10GBASE-ER<\/strong><\/a> v\u1ec1 c\u01a1 b\u1ea3n l\u00e0 l\u1ef1a ch\u1ecdn c\u00e1c PMD kh\u00e1c nhau \u0111\u01b0\u1ee3c t\u1ed1i \u01b0u h\u00f3a cho kho\u1ea3ng c\u00e1ch 300 m, 10 km ho\u1eb7c 40 km.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b.webp\" alt=\"10GBASE-SR, 10GBASE-LR, and 10GBASE-E\" class=\"wp-image-3576\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/31aebd7127984c4e95dcb31cf479990b-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f B\u1ea3ng t\u00f3m t\u1eaft v\u00ed d\u1ee5 v\u1ec1 PMD <\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Thay th\u1ebf c\u00e1c gi\u00e1 tr\u1ecb b\u1eb1ng c\u00e1c th\u00f4ng s\u1ed1 ch\u00ednh x\u00e1c t\u1eeb b\u1ea3ng d\u1eef li\u1ec7u k\u1ef9 thu\u1eadt c\u1ee7a module <\/em><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/file\/datasheet\/ls-sm3110-10c.pdf\"><em>SFP+<\/em><\/a><em>.<\/em><\/p>\n\n\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<colgroup><col style=\"width: 220px;\"\/><col style=\"width: 214px;\"\/><col style=\"min-width: 25px;\"\/><\/colgroup><tbody><tr><th colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>Thu\u1ed9c t\u00ednh PMD<\/p><\/th><th colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>Gi\u00e1 tr\u1ecb \u0111i\u1ec3n h\u00ecnh<\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p>M\u00f4 t\u1ea3<\/p><\/th><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>B\u01b0\u1edbc s\u00f3ng<br><\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>1310nm<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Laser \u0111\u01a1n ch\u1ebf \u0111\u1ed9, t\u1ea7m xa<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>C\u00f4ng su\u1ea5t ph\u00e1t (Min\/Max)<\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>\u20133 dBm \/ +3 dBm<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>D\u1ea3i c\u00f4ng su\u1ea5t ph\u00e1t<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>\u0110\u1ed9 nh\u1ea1y thu<\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>\u201314 dBm<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>C\u00f4ng su\u1ea5t t\u1ed1i thi\u1ec3u \u0111\u1ec3 \u0111\u00e1p \u1ee9ng y\u00eau c\u1ea7u BER<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>Ng\u01b0\u1ee1ng qu\u00e1 t\u1ea3i thu<\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>+1 dBm<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>C\u00f4ng su\u1ea5t \u0111\u1ea7u v\u00e0o an to\u00e0n t\u1ed1i \u0111a<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>10km, 20km, 40km<\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>10 km<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ph\u1ee5 thu\u1ed9c v\u00e0o t\u1ed5n hao s\u1ee3i quang v\u00e0 c\u00e1c m\u1ed1i n\u1ed1i<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\" colwidth=\"220\"><p>T\u1ef7 s\u1ed1 t\u1eaft m\u1edf<\/p><\/td><td colspan=\"1\" rowspan=\"1\" colwidth=\"214\"><p>\u2265 3,5 dB<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ch\u1ea5t l\u01b0\u1ee3ng \u0111i\u1ec1u ch\u1ebf laser<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f Ki\u1ec3m tra v\u00e0 x\u00e1c nh\u1eadn s\u1ef1 tu\u00e2n th\u1ee7 PMD<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Vi\u1ec7c ki\u1ec3m tra PMD \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a r\u00f5 r\u00e0ng \u0111\u1ea3m b\u1ea3o kh\u1ea3 n\u0103ng t\u01b0\u01a1ng t\u00e1c \u0111\u00e1ng tin c\u1eady.<br\/>C\u00e1c ph\u00e9p \u0111o ch\u00ednh bao g\u1ed3m:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>C\u00f4ng su\u1ea5t quang t\u1ea1i b\u1ed9 ph\u00e1t v\u00e0 b\u1ed9 thu<\/p><\/li><li><p>S\u1ef1 tu\u00e2n th\u1ee7 m\u1eb7t n\u1ea1 m\u1eaft (eye-mask)<\/p><\/li><li><p><a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/jitter-in-optics-causes-effects-measurement-reduction\/\">\u0110\u1ed9 m\u00e9o th\u1eddi gian (jitter)<\/a> v\u00e0 bi\u00ean d\u1ef1 ph\u00f2ng nhi\u1ec5u<\/p><\/li><li><p>Ki\u1ec3m tra t\u1ea1i c\u00e1c \u0111i\u1ec3m nhi\u1ec7t \u0111\u1ed9 \u0111\u00e3 quy \u0111\u1ecbnh<\/p><\/li><li><p>X\u00e1c minh \u0111\u1ed9 nh\u1ea1y thu trong \u0111i\u1ec1u ki\u1ec7n b\u1ecb \u1ee9ng su\u1ea5t<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c ph\u00e9p \u0111o n\u00e0y ph\u00f9 h\u1ee3p v\u1edbi quy tr\u00ecnh x\u00e1c nh\u1eadn s\u1ef1 tu\u00e2n th\u1ee7 IEEE.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f Kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 li\u00ean quan \u0111\u1ebfn PMD<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >C\u00f4ng su\u1ea5t thu th\u1ea5p<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra \u0111\u1ed9 s\u1ea1ch c\u1ee7a \u0111\u1ea7u n\u1ed1i, t\u1ed5n hao s\u1ee3i quang b\u1ea5t ng\u1edd ho\u1eb7c n\u1ed1i qu\u00e1 nhi\u1ec1u \u0111o\u1ea1n c\u00e1p.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Li\u00ean k\u1ebft b\u1ecb gi\u1eadt (flap) tr\u00ean c\u00e1c kho\u1ea3ng c\u00e1ch d\u00e0i<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra suy gi\u1ea3m c\u00f4ng su\u1ea5t ph\u00e1t (Tx) theo th\u1eddi gian ho\u1eb7c \u0111\u1ed9 nh\u1ea1y \u1edf ng\u01b0\u1ee1ng gi\u1edbi h\u1ea1n \u2014 ng\u00e2n s\u00e1ch quang c\u00f3 th\u1ec3 qu\u00e1 ch\u1eadt.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110a ch\u1ebf \u0111\u1ed9 \u0111\u1ea1t \u0111\u01b0\u1ee3c kho\u1ea3ng c\u00e1ch ng\u1eafn h\u01a1n d\u1ef1 ki\u1ebfn<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e1c minh t\u00ednh t\u01b0\u01a1ng th\u00edch c\u1ee7a OM3\/OM4; c\u00e1c gi\u1edbi h\u1ea1n b\u0103ng th\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o lo\u1ea1i m\u00f4i tr\u01b0\u1eddng truy\u1ec1n d\u1eabn.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" >\u27a1\ufe0f K\u1ebft lu\u1eadn<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>Ph\u1ee5 thu\u1ed9c v\u00e0o ph\u01b0\u01a1ng ti\u1ec7n v\u1eadt l\u00fd (PMD)<\/strong> t\u1ea7ng ph\u1ee5 (sublayer) l\u00e0 m\u1ed9t trong nh\u1eefng kh\u00e1i ni\u1ec7m n\u1ec1n t\u1ea3ng \u0111\u1eb1ng sau kh\u1ea3 n\u0103ng t\u01b0\u01a1ng t\u00e1c gi\u1eefa c\u00e1c thi\u1ebft b\u1ecb \u1edf t\u1ea7ng v\u1eadt l\u00fd Ethernet. B\u1eb1ng c\u00e1ch quy \u0111\u1ecbnh b\u01b0\u1edbc s\u00f3ng quang, d\u1ea3i c\u00f4ng su\u1ea5t, \u0111\u1ed9 nh\u1ea1y, kho\u1ea3ng c\u00e1ch truy\u1ec1n v\u00e0 c\u00e1c \u0111i\u1ec3m ki\u1ec3m tra, PMD \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c module thu ph\u00e1t (transceiver) t\u1eeb c\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t kh\u00e1c nhau ho\u1ea1t \u0111\u1ed9ng m\u1ed9t c\u00e1ch d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c tr\u00ean c\u00f9ng m\u1ed9t c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng c\u00e1p quang.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi c\u00e1c t\u1ed5 ch\u1ee9c tri\u1ec3n khai ho\u1eb7c n\u00e2ng c\u1ea5p m\u1ea1ng, vi\u1ec7c hi\u1ec3u r\u00f5 PMD l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t \u0111\u1ec3 l\u1ef1a ch\u1ecdn \u0111\u00fang c\u00e1c module quang v\u00e0 thi\u1ebft k\u1ebf li\u00ean k\u1ebft \u0111\u00e1ng tin c\u1eady, tu\u00e2n th\u1ee7 ti\u00eau chu\u1ea9n v\u00e0 s\u1eb5n s\u00e0ng cho t\u01b0\u01a1ng lai.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\"><strong>b\u1ed9 thu ph\u00e1t quang h\u1ecdc c\u1ee7a LINK-PP<\/strong><\/a> bao g\u1ed3m c\u00e1c \u0111\u1eb7c t\u1ea3 PMD \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh r\u00f5 r\u00e0ng, khi\u1ebfn ch\u00fang tr\u1edf th\u00e0nh nh\u1eefng l\u1ef1a ch\u1ecdn tuy\u1ec7t v\u1eddi cho c\u00e1c thi\u1ebft k\u1ebf m\u1ea1ng b\u1ec1n v\u1eefng v\u00e0 tu\u00e2n th\u1ee7 ti\u00eau chu\u1ea9n.<\/p>","protected":false},"excerpt":{"rendered":"<p>PMD (Ph\u1ee5 thu\u1ed9c v\u00e0o m\u00f4i tr\u01b0\u1eddng v\u1eadt l\u00fd) x\u00e1c \u0111\u1ecbnh c\u00e1c quy t\u1eafc quang h\u1ecdc v\u00e0 \u0111i\u1ec7n c\u1ee7a PHY\u2014b\u01b0\u1edbc s\u00f3ng, c\u00f4ng su\u1ea5t, kho\u1ea3ng c\u00e1ch truy\u1ec1n v\u00e0 \u0111i\u1ec3m ki\u1ec3m tra. Hi\u1ec3u c\u00e1c \u0111\u1eb7c t\u1ea3 PMD v\u00e0 c\u00e1ch ch\u00fang \u0111\u1ecbnh h\u01b0\u1edbng vi\u1ec7c l\u1ef1a ch\u1ecdn b\u1ed9 thu ph\u00e1t.<\/p>","protected":false},"author":1,"featured_media":3577,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[27],"tags":[24,26],"class_list":["post-3578","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-glossary","tag-link-pp","tag-optics-transceivers"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3578","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=3578"}],"version-history":[{"count":5,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3578\/revisions"}],"predecessor-version":[{"id":10826,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3578\/revisions\/10826"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media\/3577"}],"wp:attachment":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media?parent=3578"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/categories?post=3578"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/tags?post=3578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}