M\u00e1y t\u00ednh v\u00e0o m\u1ea1ng, khi kh\u00f4ng c\u00f3 \u0111\u01b0\u1eddng d\u00e2y chuy\u00ean d\u1ee5ng th\u00ec c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i. Nh\u01b0ng l\u00fac n\u00e0y ph\u1ea3i d\u00f9ng th\u00eam m\u1ed9t b\u1ed9 m\u00f4\u0111em. V\u00ec sao l\u1ea1i th\u1ebf?<\/p>\n\n\n\n
Khi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i, trong \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i truy\u1ec1n t\u1ea3i m\u1ed9t lo\u1ea1i t\u00edn hi\u1ec7u \u0111i\u1ec7n \u0111\u01b0\u1ee3c bi\u1ebfn \u0111\u1ed5i t\u1eeb t\u00edn hi\u1ec7u \u00e2m thanh. M\u1ee9c \u0111\u1ed9 l\u1edbn nh\u1ecf v\u00e0 t\u1ea7n s\u1ed1 cao th\u1ea5p hi\u1ec3n hi\u1ec7n c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n \u0111\u01b0\u1ee3c bi\u1ebfn \u0111\u1ed5i theo s\u1ef1 thay \u0111\u1ed5i c\u1ee7a \u00e2m l\u01b0\u1ee3ng v\u00e0 \u00e2m \u0111i\u1ec7u c\u1ee7a t\u00edn hi\u1ec7u \u00e2m thanh. V\u1ec1 k\u1ef9 thu\u1eadt \u0111i\u1ec7n t\u00edn, t\u00edn hi\u1ec7u n\u00e0y g\u1ecdi l\u00e0 t\u00edn hi\u1ec7u t\u01b0\u01a1ng t\u1ef1 (analog). \u0110i\u1ec7n tho\u1ea1i t\u01b0\u01a1ng \u1ee9ng g\u1ecdi l\u00e0 \u0111i\u1ec7n tho\u1ea1i t\u01b0\u01a1ng t\u1ef1 (analog). \u0110\u1ec3 c\u00f3 th\u1ec3 truy\u1ec1n t\u1ea3i b\u00ecnh th\u01b0\u1eddng trong \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i, d\u01b0\u1edbi t\u00e1c d\u1ee5ng c\u1ee7a thi\u1ebft b\u1ecb l\u1ecdc s\u00f3ng c\u00f3 th\u1ec3 \u0111i\u1ec1u khi\u1ec3n ph\u1ea1m vi thay \u0111\u1ed5i t\u1ea7n s\u1ed1 \u0111\u1ed1i v\u1edbi t\u00edn hi\u1ec7u \u0111i\u1ec7n, s\u1ef1 thay \u0111\u1ed5i c\u1ee7a t\u1ea7n s\u1ed1 t\u00edn hi\u1ec7u \u0111i\u1ec7n m\u00f4 ph\u1ecfng b\u1ecb h\u1ea1n ch\u1ebf trong ph\u1ea1m vi h\u1eb9p c\u00f3 th\u1ec3 ti\u1ebfn h\u00e0nh truy\u1ec1n th\u00f4ng b\u00ecnh th\u01b0\u1eddng.<\/p>\n\n\n\n
\u0110\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i ph\u1ea7n l\u1edbn l\u00e0 m\u1ed9t lo\u1ea1i d\u00e2y s\u00fap l\u00f5i \u0111\u1ed3ng \u0111\u01a1n. L\u00e0 v\u1eadt truy\u1ec1n t\u1ea3i t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u00edn, \u0111\u1eb7c t\u00ednh truy\u1ec1n t\u1ea3i c\u1ee7a n\u00f3 t\u1ed1t hay x\u1ea5u l\u00e0 c\u00f3 li\u00ean quan m\u1eadt thi\u1ebft v\u1edbi ph\u1ea1m vi thay \u0111\u1ed5i t\u1ea7n s\u1ed1 c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u00edn. Ph\u1ea1m vi t\u1ea7n s\u1ed1 (d\u1ea3i t\u1ea7n) c\u00e0ng r\u1ed9ng, \u0111\u1eb7c t\u00ednh truy\u1ec1n t\u1ea3i c\u00e0ng k\u00e9m. B\u1edfi v\u00ec ph\u1ea1m vi thay \u0111\u1ed5i t\u1ea7n s\u1ed1 c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng t\u1ef1 r\u1ea5t h\u1eb9p, cao nh\u1ea5t c\u0169ng ch\u1ec9 trong ph\u1ea1m vi truy\u1ec1n t\u1ea3i b\u00ecnh th\u01b0\u1eddng c\u1ee7a d\u00e2y s\u00fap \u0111\u1ed3ng. Cho n\u00ean, t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng t\u1ef1 c\u00f3 th\u1ec3 thu\u1eadn l\u1ee3i ch\u1ea1y qua d\u00e2y s\u00fap \u0111\u1ed3ng m\u00e0 kh\u00f4ng b\u1ecb \u1ea3nh h\u01b0\u1edfng. \u00c2m thanh \u0111i\u1ec7n tho\u1ea1i r\u00f5 r\u00e0ng, \u1ed5n \u0111\u1ecbnh.<\/p>\n\n\n\n
V\u1edbi m\u00e1y t\u00ednh v\u00e0o m\u1ea1ng, c\u00e1c truy\u1ec1n t\u1ea3i qua l\u1ea1i trong \u0111\u01b0\u1eddng d\u00e2y \u0111\u1ec1u l\u00e0 t\u00edn hi\u1ec7u s\u1ed1. T\u00edn hi\u1ec7u s\u1ed1 so v\u1edbi t\u00edn hi\u1ec7u t\u01b0\u01a1ng t\u1ef1 th\u00ec ph\u1ea1m vi thay \u0111\u1ed5i t\u1ea7n s\u1ed1 r\u1ed9ng h\u01a1n nhi\u1ec1u. T\u1ea7n s\u1ed1 \u0111\u1ec9nh cao c\u0169ng cao h\u01a1n h\u1eb3n. N\u1ebfu n\u1ed1i tr\u1ef1c ti\u1ebfp m\u00e1y t\u00ednh tr\u00ean \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i th\u00ec t\u00edn hi\u1ec7u \u0111i\u1ec7n c\u1ee7a con s\u1ed1 khi truy\u1ec1n t\u1ea3i tr\u00ean d\u00e2y s\u00fap \u0111\u1ed3ng s\u1ebd x\u1ea3y ra “hi\u1ec7u \u1ee9ng m\u1eb7t ngo\u00e0i” (hi\u1ec7n t\u01b0\u1ee3ng khi d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u ch\u1ea1y qua v\u1eadt d\u1eabn \u0111i\u1ec7n, do t\u00e1c d\u1ee5ng c\u1ea3m \u1ee9ng m\u00e0 s\u1ef1 ph\u00e2n b\u1ed1 d\u00f2ng \u0111i\u1ec7n tr\u00ean ti\u1ebft di\u1ec7n v\u1eadt d\u1eabn kh\u00f4ng \u0111\u1ec1u, c\u00e0ng g\u1ea7n b\u1ec1 m\u1eb7t v\u1eadt d\u1eabn th\u00ec m\u1eadt \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n c\u00e0ng l\u1edbn. Hi\u1ec7u \u1ee9ng n\u00e0y l\u00e0m cho \u0111i\u1ec7n tr\u1edf h\u1eefu hi\u1ec7u c\u1ee7a v\u1eadt d\u1eabn c\u00e0ng t\u0103ng. T\u1ea7n s\u1ed1 c\u00e0ng cao, hi\u1ec7u \u1ee9ng m\u1eb7t ngo\u00e0i (skin effect) c\u00e0ng r\u00f5 (ch\u00fa th\u00edch c\u1ee7a ng\u01b0\u1eddi d\u1ecbch) trong k\u1ef9 thu\u1eadt \u0111i\u1ec7n t\u1eed. N\u00f3 s\u1ebd c\u00f3 t\u00e1c d\u1ee5ng c\u1ea3n tr\u1edf v\u1edbi t\u00edn hi\u1ec7u \u0111i\u1ec7n, t\u00edn hi\u1ec7n \u0111i\u1ec7n s\u1ebd bi\u1ebfn \u0111\u1ed5i b\u1ea5t th\u01b0\u1eddng, kh\u00f4ng c\u00f2n th\u1eadt n\u1eefa.<\/p>\n\n\n\n
Thi\u1ebft b\u1ecb \u0111i\u1ec1u ch\u1ebf (bi\u1ebfn \u0111i\u1ec7u) c\u00f3 th\u1ec3 bi\u1ebfn \u0111\u1ed5i d\u1ea3i t\u1ea7n s\u1ed1 c\u1ef1c r\u1ed9ng c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n c\u1ee7a con s\u1ed1 th\u00e0nh d\u1ea3i t\u1ea7n s\u1ed1 gi\u1ed1ng v\u1edbi t\u00edn hi\u1ec7u \u0111i\u1ec7n m\u00f4 ph\u1ecfng. Nh\u01b0 v\u1eady, t\u00edn hi\u1ec7u s\u1ed1 khi truy\u1ec1n t\u1ea3i tr\u00ean \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i s\u1ebd \u0111\u01b0\u1ee3c d\u00e2y s\u00fap \u0111\u1ed3ng \u0111\u1ed1i x\u1eed b\u00ecnh \u0111\u1eb3ng. Ch\u1ea5t l\u01b0\u1ee3ng truy\u1ec1n t\u1ea3i s\u1ebd \u0111\u01b0\u1ee3c b\u1ea3o \u0111\u1ea3m. T\u00e1c d\u1ee5ng c\u1ee7a thi\u1ebft b\u1ecb gi\u1ea3i \u0111i\u1ec1u (kh\u1eed bi\u1ebfn \u0111i\u1ec7u) l\u00e0 ho\u00e0n nguy\u00ean th\u00e0nh d\u1ea1ng ban \u0111\u1ea7u c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n c\u1ee7a con s\u1ed1 v\u1edbi d\u1ea3i t\u1ea7n s\u1ed1 \u0111\u00e3 b\u1ecb thu h\u1eb9p. M\u00f4\u0111em \u0111\u00e3 t\u1ea1o n\u00ean s\u1ef1 li\u00ean h\u1ec7 hai chi\u1ec1u gi\u1eefa ng\u01b0\u1eddi s\u1eed d\u1ee5ng m\u00e1y t\u00ednh v\u00e0 trung t\u00e2m li\u00ean l\u1ea1c. Do thi\u1ebft b\u1ecb \u0111i\u1ec1u ch\u1ebf v\u00e0 thi\u1ebft b\u1ecb gi\u1ea3i \u0111i\u1ec1u \u0111\u1ec1u n\u1eb1m m\u1ed9t ch\u1ed7 m\u00e0 ta g\u1ecdi n\u00f3 l\u00e0 thi\u1ebft b\u1ecb \u0111i\u1ec1u ch\u1ebf – gi\u1ea3i \u0111i\u1ec1u, bi\u1ec3u th\u1ecb l\u00e0 m\u00f4\u0111em.<\/p>\n\n\n\n
C\u00f3 \u0111\u01b0\u1ee3c m\u00f4\u0111em th\u00ec tr\u00ean c\u00f9ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i, ta v\u1eeba c\u00f3 th\u1ec3 g\u1ecdi \u0111i\u1ec7n tho\u1ea1i, v\u1eeba c\u00f3 th\u1ec3 v\u00e0o m\u1ea1ng. N\u1ebfu \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i s\u1eed d\u1ee5ng c\u00e1p \u0111i\u1ec7n s\u1ee3i quang c\u00f3 \u0111\u1eb7c t\u00ednh truy\u1ec1n t\u1ea3i d\u1ea3i t\u1ea7n r\u1ed9ng th\u00ec tr\u00ean m\u1ed9t \u0111\u00f4i c\u00e1p quang s\u1ebd c\u00f3 th\u1ec3 \u0111\u1ed3ng th\u1eddi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i, v\u00e0o m\u1ea1ng, thu ph\u00e1t fax v\u00e0 xem truy\u1ec1n h\u00ecnh h\u1eefu tuy\u1ebfn \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n
T\u1eeb kh\u00f3a: \u0110i\u1ec7n tho\u1ea1i; T\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng t\u01b0; T\u00edn hi\u1ec7u \u0111i\u1ec7n s\u1ed1.<\/p>\n","protected":false},"excerpt":{"rendered":"
M\u00e1y t\u00ednh v\u00e0o m\u1ea1ng, khi kh\u00f4ng c\u00f3 \u0111\u01b0\u1eddng d\u00e2y chuy\u00ean d\u1ee5ng th\u00ec c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i. Nh\u01b0ng l\u00fac n\u00e0y ph\u1ea3i d\u00f9ng th\u00eam m\u1ed9t b\u1ed9 m\u00f4\u0111em. V\u00ec sao l\u1ea1i th\u1ebf? Khi g\u1ecdi \u0111i\u1ec7n tho\u1ea1i, trong \u0111\u01b0\u1eddng d\u00e2y \u0111i\u1ec7n tho\u1ea1i truy\u1ec1n t\u1ea3i m\u1ed9t lo\u1ea1i t\u00edn hi\u1ec7u \u0111i\u1ec7n \u0111\u01b0\u1ee3c bi\u1ebfn \u0111\u1ed5i t\u1eeb t\u00edn hi\u1ec7u […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[15,13],"tags":[],"class_list":["post-10380","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-tin-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/10380","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=10380"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/10380\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=10380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=10380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=10380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}