{"id":47452,"date":"2023-04-22T00:18:49","date_gmt":"2023-04-22T05:18:49","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/how-to-measure-ultrasonic-frequency\/"},"modified":"2025-01-21T07:20:52","modified_gmt":"2025-01-21T12:20:52","slug":"how-to-measure-ultrasonic-frequency","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/vi\/how-to-measure-ultrasonic-frequency\/","title":{"rendered":"\u0110o T\u1ea7n S\u1ed1 Si\u00eau \u00c2m: Ph\u01b0\u01a1ng Ph\u00e1p &#038; K\u1ef9 Thu\u1eadt"},"content":{"rendered":"<p>T\u1ea7n s\u1ed1 si\u00eau \u00e2m l\u00e0 m\u1ed9t th\u00f4ng s\u1ed1 quan tr\u1ecdng quy\u1ebft \u0111\u1ecbnh \u0111\u1eb7c t\u00ednh v\u00e0 \u1ee9ng d\u1ee5ng c\u1ee7a s\u00f3ng si\u00eau \u00e2m. Vi\u1ec7c \u0111o l\u01b0\u1eddng ch\u00ednh x\u00e1c t\u1ea7n s\u1ed1 n\u00e0y l\u00e0 c\u1ea7n thi\u1ebft trong nhi\u1ec1u l\u0129nh v\u1ef1c, t\u1eeb y t\u1ebf v\u00e0 c\u00f4ng nghi\u1ec7p \u0111\u1ebfn nghi\u00ean c\u1ee9u khoa h\u1ecdc. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd tr\u00ecnh b\u00e0y chi ti\u1ebft c\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111o t\u1ea7n s\u1ed1 si\u00eau \u00e2m, t\u1eeb nh\u1eefng k\u1ef9 thu\u1eadt \u0111\u01a1n gi\u1ea3n \u0111\u1ebfn nh\u1eefng ph\u01b0\u01a1ng ph\u00e1p ph\u1ee9c t\u1ea1p h\u01a1n.<\/p>\n<h3>S\u1eed d\u1ee5ng m\u00e1y hi\u1ec7n s\u00f3ng (Oscilloscope)<\/h3>\n<p>M\u00e1y hi\u1ec7n s\u00f3ng l\u00e0 m\u1ed9t trong nh\u1eefng c\u00f4ng c\u1ee5 ph\u1ed5 bi\u1ebfn nh\u1ea5t \u0111\u1ec3 \u0111o t\u1ea7n s\u1ed1 si\u00eau \u00e2m. B\u1eb1ng c\u00e1ch k\u1ebft n\u1ed1i \u0111\u1ea7u d\u00f2 si\u00eau \u00e2m v\u1edbi m\u00e1y hi\u1ec7n s\u00f3ng, ta c\u00f3 th\u1ec3 quan s\u00e1t d\u1ea1ng s\u00f3ng c\u1ee7a t\u00edn hi\u1ec7u si\u00eau \u00e2m. T\u1eeb d\u1ea1ng s\u00f3ng n\u00e0y, ta c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh chu k\u1ef3 c\u1ee7a s\u00f3ng v\u00e0 t\u1eeb \u0111\u00f3 t\u00ednh to\u00e1n t\u1ea7n s\u1ed1 b\u1eb1ng c\u00f4ng th\u1ee9c f = 1\/T, v\u1edbi f l\u00e0 t\u1ea7n s\u1ed1 v\u00e0 T l\u00e0 chu k\u1ef3. \u01afu \u0111i\u1ec3m c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p n\u00e0y l\u00e0 tr\u1ef1c quan v\u00e0 d\u1ec5 th\u1ef1c hi\u1ec7n. Tuy nhi\u00ean, \u0111\u1ed9 ch\u00ednh x\u00e1c ph\u1ee5 thu\u1ed9c v\u00e0o \u0111\u1ed9 ph\u00e2n gi\u1ea3i c\u1ee7a m\u00e1y hi\u1ec7n s\u00f3ng.<\/p>\n<h3>S\u1eed d\u1ee5ng m\u00e1y ph\u00e2n t\u00edch ph\u1ed5 (Spectrum Analyzer)<\/h3>\n<p>M\u00e1y ph\u00e2n t\u00edch ph\u1ed5 l\u00e0 m\u1ed9t thi\u1ebft b\u1ecb chuy\u00ean d\u1ee5ng \u0111\u1ec3 ph\u00e2n t\u00edch c\u00e1c th\u00e0nh ph\u1ea7n t\u1ea7n s\u1ed1 c\u1ee7a m\u1ed9t t\u00edn hi\u1ec7u. Khi s\u1eed d\u1ee5ng m\u00e1y ph\u00e2n t\u00edch ph\u1ed5 \u0111\u1ec3 \u0111o t\u1ea7n s\u1ed1 si\u00eau \u00e2m, ta c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c t\u1ea7n s\u1ed1 ch\u00ednh x\u00e1c c\u0169ng nh\u01b0 c\u00e1c t\u1ea7n s\u1ed1 h\u00e0i (harmonics) c\u00f3 trong t\u00edn hi\u1ec7u. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y cho \u0111\u1ed9 ch\u00ednh x\u00e1c cao h\u01a1n so v\u1edbi m\u00e1y hi\u1ec7n s\u00f3ng v\u00e0 c\u0169ng cung c\u1ea5p th\u00eam th\u00f4ng tin v\u1ec1 ph\u1ed5 t\u1ea7n s\u1ed1 c\u1ee7a t\u00edn hi\u1ec7u.<\/p>\n<h3>S\u1eed d\u1ee5ng b\u1ed9 \u0111\u1ebfm t\u1ea7n s\u1ed1 (Frequency Counter)<\/h3>\n<p>B\u1ed9 \u0111\u1ebfm t\u1ea7n s\u1ed1 l\u00e0 m\u1ed9t thi\u1ebft b\u1ecb \u0111i\u1ec7n t\u1eed \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 \u0111o t\u1ea7n s\u1ed1 c\u1ee7a m\u1ed9t t\u00edn hi\u1ec7u.  Khi s\u1eed d\u1ee5ng b\u1ed9 \u0111\u1ebfm t\u1ea7n s\u1ed1, t\u00edn hi\u1ec7u si\u00eau \u00e2m \u0111\u01b0\u1ee3c \u0111\u01b0a v\u00e0o thi\u1ebft b\u1ecb v\u00e0 t\u1ea7n s\u1ed1 s\u1ebd \u0111\u01b0\u1ee3c hi\u1ec3n th\u1ecb tr\u1ef1c ti\u1ebfp tr\u00ean m\u00e0n h\u00ecnh.  Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y r\u1ea5t \u0111\u01a1n gi\u1ea3n v\u00e0 cho k\u1ebft qu\u1ea3 nhanh ch\u00f3ng, \u0111\u1ed9 ch\u00ednh x\u00e1c cao. Tuy nhi\u00ean, c\u1ea7n l\u01b0u \u00fd ch\u1ecdn b\u1ed9 \u0111\u1ebfm t\u1ea7n s\u1ed1 c\u00f3 d\u1ea3i t\u1ea7n s\u1ed1 ph\u00f9 h\u1ee3p v\u1edbi t\u1ea7n s\u1ed1 si\u00eau \u00e2m c\u1ea7n \u0111o.<\/p>\n<h3>Ph\u01b0\u01a1ng ph\u00e1p \u0111o gi\u00e1n ti\u1ebfp d\u1ef1a tr\u00ean b\u01b0\u1edbc s\u00f3ng<\/h3>\n<p>T\u1ea7n s\u1ed1 si\u00eau \u00e2m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh gi\u00e1n ti\u1ebfp th\u00f4ng qua b\u01b0\u1edbc s\u00f3ng c\u1ee7a n\u00f3. B\u01b0\u1edbc s\u00f3ng (\u03bb) li\u00ean h\u1ec7 v\u1edbi t\u1ea7n s\u1ed1 (f) v\u00e0 t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng (v) theo c\u00f4ng th\u1ee9c: \u03bb = v\/f.  B\u1eb1ng c\u00e1ch \u0111o b\u01b0\u1edbc s\u00f3ng v\u00e0 bi\u1ebft t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng trong m\u00f4i tr\u01b0\u1eddng, ta c\u00f3 th\u1ec3 t\u00ednh to\u00e1n t\u1ea7n s\u1ed1.  Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c \u1ee9ng d\u1ee5ng \u0111o l\u01b0\u1eddng kh\u00f4ng ph\u00e1 h\u1ee7y.<\/p>\n<table class=\"table table-striped table-bordered\">\n<thead>\n<tr>\n<th>Ph\u01b0\u01a1ng ph\u00e1p<\/th>\n<th>\u01afu \u0111i\u1ec3m<\/th>\n<th>Nh\u01b0\u1ee3c \u0111i\u1ec3m<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>M\u00e1y hi\u1ec7n s\u00f3ng<\/td>\n<td>Tr\u1ef1c quan, d\u1ec5 th\u1ef1c hi\u1ec7n<\/td>\n<td>\u0110\u1ed9 ch\u00ednh x\u00e1c ph\u1ee5 thu\u1ed9c v\u00e0o m\u00e1y<\/td>\n<\/tr>\n<tr>\n<td>M\u00e1y ph\u00e2n t\u00edch ph\u1ed5<\/td>\n<td>\u0110\u1ed9 ch\u00ednh x\u00e1c cao, ph\u00e2n t\u00edch \u0111\u01b0\u1ee3c ph\u1ed5 t\u1ea7n s\u1ed1<\/td>\n<td>Chi ph\u00ed cao<\/td>\n<\/tr>\n<tr>\n<td>B\u1ed9 \u0111\u1ebfm t\u1ea7n s\u1ed1<\/td>\n<td>\u0110\u01a1n gi\u1ea3n, nhanh ch\u00f3ng, ch\u00ednh x\u00e1c<\/td>\n<td>C\u1ea7n ch\u1ecdn \u0111\u00fang d\u1ea3i t\u1ea7n s\u1ed1<\/td>\n<\/tr>\n<tr>\n<td>\u0110o gi\u00e1n ti\u1ebfp qua b\u01b0\u1edbc s\u00f3ng<\/td>\n<td>\u00c1p d\u1ee5ng \u0111\u01b0\u1ee3c trong nhi\u1ec1u tr\u01b0\u1eddng h\u1ee3p<\/td>\n<td>C\u1ea7n bi\u1ebft t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Vi\u1ec7c l\u1ef1a ch\u1ecdn ph\u01b0\u01a1ng ph\u00e1p \u0111o t\u1ea7n s\u1ed1 si\u00eau \u00e2m ph\u1ee5 thu\u1ed9c v\u00e0o y\u00eau c\u1ea7u v\u1ec1 \u0111\u1ed9 ch\u00ednh x\u00e1c, chi ph\u00ed v\u00e0 t\u00ednh ch\u1ea5t c\u1ee7a \u1ee9ng d\u1ee5ng.  T\u1eeb c\u00e1c ph\u01b0\u01a1ng ph\u00e1p \u0111\u01a1n gi\u1ea3n nh\u01b0 s\u1eed d\u1ee5ng m\u00e1y hi\u1ec7n s\u00f3ng \u0111\u1ebfn c\u00e1c ph\u01b0\u01a1ng ph\u00e1p ph\u1ee9c t\u1ea1p h\u01a1n nh\u01b0 s\u1eed d\u1ee5ng m\u00e1y ph\u00e2n t\u00edch ph\u1ed5, ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 l\u1ef1a ch\u1ecdn ph\u01b0\u01a1ng ph\u00e1p ph\u00f9 h\u1ee3p nh\u1ea5t \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o \u0111o l\u01b0\u1eddng t\u1ea7n s\u1ed1 si\u00eau \u00e2m m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c v\u00e0 hi\u1ec7u qu\u1ea3.  Hi\u1ec3u r\u00f5 nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng v\u00e0 \u01b0u nh\u01b0\u1ee3c \u0111i\u1ec3m c\u1ee7a t\u1eebng ph\u01b0\u01a1ng ph\u00e1p s\u1ebd gi\u00fap t\u1ed1i \u01b0u h\u00f3a qu\u00e1 tr\u00ecnh \u0111o l\u01b0\u1eddng v\u00e0 \u0111\u1ea1t \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 mong mu\u1ed1n.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>T\u1ea7n s\u1ed1 si\u00eau \u00e2m l\u00e0 m\u1ed9t th\u00f4ng s\u1ed1 quan tr\u1ecdng quy\u1ebft \u0111\u1ecbnh \u0111\u1eb7c t\u00ednh v\u00e0 \u1ee9ng d\u1ee5ng c\u1ee7a s\u00f3ng si\u00eau \u00e2m. Vi\u1ec7c \u0111o l\u01b0\u1eddng ch\u00ednh x\u00e1c t\u1ea7n s\u1ed1 n\u00e0y l\u00e0 c\u1ea7n thi\u1ebft trong nhi\u1ec1u l\u0129nh v\u1ef1c, t\u1eeb y t\u1ebf v\u00e0 c\u00f4ng nghi\u1ec7p \u0111\u1ebfn nghi\u00ean c\u1ee9u khoa h\u1ecdc. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd tr\u00ecnh b\u00e0y chi ti\u1ebft<\/p>\n","protected":false},"author":1,"featured_media":26473,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6406],"tags":[],"class_list":["post-47452","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","prodpage-classic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/posts\/47452","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/comments?post=47452"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/posts\/47452\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/media\/26473"}],"wp:attachment":[{"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/media?parent=47452"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/categories?post=47452"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/vi\/wp-json\/wp\/v2\/tags?post=47452"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}