{"id":5936,"date":"2021-11-20T10:13:03","date_gmt":"2021-11-20T03:13:03","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=5936"},"modified":"2021-11-20T13:24:11","modified_gmt":"2021-11-20T06:24:11","slug":"vi-sao-bang-tu-co-the-ghi-am-ghi-hinh","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/vi-sao-bang-tu-co-the-ghi-am-ghi-hinh\/","title":{"rendered":"V\u00ec sao b\u0103ng t\u1eeb c\u00f3 th\u1ec3 ghi \u00e2m, ghi h\u00ecnh?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">B\u0103ng t\u1eeb ghi \u00e2m v\u00e0 ghi h\u00ecnh \u0111\u01b0\u1ee3c l\u00e0m ra do m\u1ed9t lo\u1ea1i h\u1ea1t b\u1ed9t t\u1eeb h\u1ebft s\u1ee9c nh\u1ecf m\u1ecbn, c\u1ed9ng th\u00eam ch\u1ea5t k\u1ebft d\u00ednh, ph\u1ebft h\u1ebft s\u1ee9c \u0111\u1ed3ng \u0111\u1ec1u l\u00ean n\u1ec1n c\u1ee7a d\u1ea3i b\u0103ng terilen m\u00e0 th\u00e0nh. Nh\u1eefng h\u1ea1t b\u1ed9t t\u1eeb n\u00e0y s\u1eafp x\u1ebfp r\u1ea5t d\u00e0y \u0111\u1eb7c, khi ch\u1ecbu s\u1ef1 bi\u1ebfn \u0111\u1ed5i c\u1ee7a t\u1eeb tr\u01b0\u1eddng, tr\u00ean m\u1eb7t ch\u00fang li\u1ec1n l\u01b0u l\u1ea1i t\u1eeb d\u01b0.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1eeb d\u01b0 bi\u1ebfn \u0111\u1ed5i theo s\u1ef1 bi\u1ebfn \u0111\u1ed5i c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 t\u1eeb tr\u01b0\u1eddng. Khi ti\u1ebfn h\u00e0nh ghi \u00e2m ho\u1eb7c ghi h\u00ecnh l\u00ean b\u0103ng t\u1eeb th\u00ec ph\u1ea3i th\u00f4ng qua micro ho\u1eb7c m\u00e1y quay truy\u1ec1n h\u00ecnh bi\u1ebfn \u00e2m thanh ho\u1eb7c h\u00ecnh \u1ea3nh th\u00e0nh t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng \u1ee9ng tr\u01b0\u1edbc \u0111\u00e3, r\u1ed3i l\u1ea1i th\u00f4ng qua \u0111\u1ea7u t\u1eeb c\u1ee7a m\u00e1y ghi \u00e2m ho\u1eb7c m\u00e1y ghi h\u00ecnh bi\u1ebfn nh\u1eefng t\u00edn hi\u1ec7u \u0111i\u1ec7n \u0111\u00f3 th\u00e0nh s\u1ef1 bi\u1ebfn \u0111\u1ed5i m\u1ea1nh y\u1ebfu c\u1ee7a t\u1eeb tr\u01b0\u1eddng. \u0110\u1ea7u t\u1eeb l\u00e0 m\u1ed9t nam ch\u00e2m \u0111i\u1ec7n \u0111\u1eb7c bi\u1ec7t. Tr\u00ean \u0111\u1ec9nh c\u1ee7a \u0111\u1ea7u t\u1eeb c\u00f3 m\u1ed9t khe h\u1edf. Khi b\u0103ng t\u1eeb ch\u1ea1y qua khe h\u1edf c\u1ee7a \u0111\u1ea7u t\u1eeb, d\u00f2ng \u0111i\u1ec7n t\u00edn hi\u1ec7u th\u00f4ng v\u00e0o trong cu\u1ed9n d\u00e2y c\u1ee7a \u0111\u1ea7u t\u1eeb, tr\u00ean b\u0103ng t\u1eeb k\u1ec1 s\u00e1t khe h\u1edf c\u1ee7a \u0111\u1ea7u t\u1eeb li\u1ec1n c\u00f3 \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u0111i qua, b\u0103ng t\u1eeb b\u1ecb t\u1eeb ho\u00e1, s\u1ef1 thay \u0111\u1ed5i c\u1ee7a t\u00edn hi\u1ec7u \u0111i\u1ec7n li\u1ec1n \u0111\u01b0\u1ee3c ghi l\u1ea1i tr\u00ean b\u0103ng t\u1eeb th\u00f4ng qua s\u1ef1 bi\u1ebfn \u0111\u1ed5i c\u1ee7a t\u1eeb tr\u01b0\u1eddng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Khi ph\u00e1t l\u1ea1i s\u1ebd l\u00e0 s\u1ef1 \u0111\u1ea3o ng\u01b0\u1ee3c c\u1ee7a qu\u00e1 tr\u00ecnh n\u00f3i tr\u00ean. T\u1ee9c l\u00e0 ho\u00e0n nguy\u00ean s\u1ef1 bi\u1ebfn \u0111\u1ed5i m\u1ea1nh y\u1ebfu c\u1ee7a t\u1eeb tr\u01b0\u1eddng \u0111\u01b0\u1ee3c ghi l\u1ea1i tr\u00ean b\u0103ng t\u1eeb th\u00e0nh t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng \u1ee9ng, r\u1ed3i l\u1ea1i \u0111\u01b0a t\u00edn hi\u1ec7u \u0111i\u1ec7n \u0111\u00f3, sau khi \u0111\u00e3 qua x\u1eed l\u00ed v\u00e0 khu\u1ebfch \u0111\u1ea1i, v\u00e0o loa ho\u1eb7c v\u00e0o b\u00f3ng hi\u1ec7n h\u00ecnh c\u1ee7a thi\u1ebft b\u1ecb nh\u00ecn truy\u1ec1n h\u00ecnh th\u00ec c\u00f3 th\u1ec3 ph\u00e1t ra \u00e2m thanh ho\u1eb7c hi\u1ec7n r\u00f5 h\u00ecnh \u1ea3nh ban \u0111\u1ea7u. Do nguy\u00ean l\u00ed ho\u1ea1t \u0111\u1ed9ng c\u1ee7a b\u0103ng t\u1eeb ghi \u00e2m, ghi h\u00ecnh gi\u1ed1ng nhau, cho n\u00ean, khi ghi h\u00ecnh l\u00ean b\u0103ng t\u1eeb ghi h\u00ecnh, \u0111\u1ed3ng th\u1eddi c\u0169ng c\u00f3 th\u1ec3 ghi \u00e2m.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u1ed1 nhi\u00ean, s\u1ef1 s\u1ea3n xu\u1ea5t b\u0103ng t\u1eeb ghi h\u00ecnh ph\u1ee9c t\u1ea1p h\u01a1n nhi\u1ec1u v\u00e0 c\u0169ng nghi\u00eam ng\u1eb7t h\u01a1n nhi\u1ec1u so v\u1edbi b\u0103ng t\u1eeb ghi \u00e2m. \u0110\u00f3 l\u00e0 v\u00ec s\u1ef1 bi\u1ebfn \u0111\u1ed5i t\u1ea7n s\u1ed1 c\u1ee7a \u00e2m thanh, n\u00f3i chung l\u00e0 trong ph\u1ea1m vi t\u1eeb v\u00e0i ch\u1ee5c Hz \u0111\u1ebfn 20 kHz n\u00ean ghi \u00e2m v\u00e0 ph\u00e1t l\u1ea1i \u0111\u1ec1u t\u01b0\u01a1ng \u0111\u1ed1i \u0111\u01a1n gi\u1ea3n. C\u00f2n khi ghi h\u00ecnh th\u00ec v\u1edbi m\u1ed9t h\u00ecnh t\u01b0\u1ee3ng h\u1ebft s\u1ee9c \u0111\u01a1n gi\u1ea3n v\u00e0 m\u1ed9t h\u00ecnh t\u01b0\u1ee3ng h\u1ebft s\u1ee9c ph\u1ee9c t\u1ea1p tinh vi, t\u00edn hi\u1ec7u \u0111i\u1ec7n t\u01b0\u01a1ng \u1ee9ng c\u1ee7a ch\u00fang c\u00f3 d\u1ea3i t\u1ea7n s\u1ed1 r\u1ea5t r\u1ed9ng, h\u1ea7u nh\u01b0 t\u1eeb 0 hec \u0111\u1ebfn v\u00e0i megahec.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1eeb kho\u00e1: Ghi \u00e2m; Ghi h\u00ecnh; B\u0103ng t\u1eeb; T\u1eeb tr\u01b0\u1eddng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"<p>B\u0103ng t\u1eeb ghi \u00e2m v\u00e0 ghi h\u00ecnh \u0111\u01b0\u1ee3c l\u00e0m ra do m\u1ed9t lo\u1ea1i h\u1ea1t b\u1ed9t t\u1eeb h\u1ebft s\u1ee9c nh\u1ecf m\u1ecbn, c\u1ed9ng th\u00eam ch\u1ea5t k\u1ebft d\u00ednh, ph\u1ebft h\u1ebft s\u1ee9c \u0111\u1ed3ng \u0111\u1ec1u l\u00ean n\u1ec1n c\u1ee7a d\u1ea3i b\u0103ng terilen m\u00e0 th\u00e0nh. Nh\u1eefng h\u1ea1t b\u1ed9t t\u1eeb n\u00e0y s\u1eafp x\u1ebfp r\u1ea5t d\u00e0y \u0111\u1eb7c, khi ch\u1ecbu s\u1ef1 bi\u1ebfn \u0111\u1ed5i c\u1ee7a t\u1eeb [&hellip;]<\/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":[15,7],"tags":[],"class_list":["post-5936","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-vat-ly"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5936","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=5936"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5936\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=5936"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=5936"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=5936"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}