{"id":2259,"date":"2015-07-01T00:00:54","date_gmt":"2015-06-30T15:00:54","guid":{"rendered":"https:\/\/micronix-jp.com\/?p=2259"},"modified":"2023-07-31T16:42:03","modified_gmt":"2023-07-31T07:42:03","slug":"emikeisan_j","status":"publish","type":"post","link":"https:\/\/micronix-jp.com\/english\/note\/application\/emikeisan_j.html","title":{"rendered":"An EMI estimation method by simple evaluation of radiated emission"},"content":{"rendered":"<p class=\"has-large-font-size\"><strong>Simple and low-cost EMI estimation by using spectru m\/signal analyzer(338E\/438E\/538E\/558E)<\/strong> <\/p><div class=\"wp-block-vk-blocks-table-of-contents-new vk_tableOfContents vk_tableOfContents-style-default tabs\"><div class=\"tab\"><div class=\"vk_tableOfContents_title\">\u76ee\u6b21<\/div><input type=\"checkbox\" id=\"chck1\"\/><label class=\"tab-label vk_tableOfContents_openCloseBtn button_status button_status-close\" for=\"chck1\"><\/label><ul class=\"vk_tableOfContents_list tab_content-close\"><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-2\" data-reactroot=\"\"><a href=\"#vk-htags-8f49382c-3a9d-4d27-b9dd-bf484c825700\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">1. <\/span>Application<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-2\" data-reactroot=\"\"><a href=\"#vk-htags-ca40c3f2-6936-465e-9b2e-cb7bf02b2bd3\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">2. <\/span>Solution<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-3\" data-reactroot=\"\"><a href=\"#vk-htags-70aebb54-2f71-42d9-a7f3-7b5fe21c9768\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">2.1. <\/span>Condition<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-3\" data-reactroot=\"\"><a href=\"#vk-htags-fc0fe98c-8759-477f-8fbb-83cd66720e70\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">2.2. <\/span>Calculation method to estimate EMI from EUT<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-3\" data-reactroot=\"\"><a href=\"#vk-htags-d6c8cc6a-b485-4f19-92a0-fb198f0edd12\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">2.3. <\/span>Discussion<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-2\" data-reactroot=\"\"><a href=\"#vk-htags-bfee73ad-7bfa-4cfa-939d-c69ffb2efa29\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">3. <\/span>System configuration<\/a><\/li><li class=\"vk_tableOfContents_list_item vk_tableOfContents_list_item-h-2\" data-reactroot=\"\"><a href=\"#vk-htags-33bee439-d6ee-48ca-bd66-ea17d7acbc35\" class=\"vk_tableOfContents_list_item_link\"><span class=\"vk_tableOfContents_list_item_link_preNumber\">4. <\/span>Products introduction<\/a><\/li><\/ul><\/div><\/div><h2 class=\"wp-block-heading\" id=\"vk-htags-8f49382c-3a9d-4d27-b9dd-bf484c825700\">Application<\/h2><p> Precompliance EMI test system MR2300 using spectrum\/sign al analyzer (338E\/438E\/538E\/558E) and anechoic box has superior cost performance. This paper presents furt her  low-cost EMI estimation method. <\/p><h2 class=\"vk_block-margin-lg--margin-top wp-block-heading\" id=\"vk-htags-ca40c3f2-6936-465e-9b2e-cb7bf02b2bd3\">Solution<\/h2><h3 class=\"wp-block-heading\" id=\"vk-htags-70aebb54-2f71-42d9-a7f3-7b5fe21c9768\">Condition<\/h3><p>EMI from EUT might be estimated by evaluating radiated em issions in a normal laboratory, if the following conditions are met.<\/p><figure class=\"wp-block-flexible-table-block-table\"><table class=\"\"><thead><tr><th style=\"text-align:center\">Condition<\/th><th style=\"text-align:center\">Description<\/th><\/tr><\/thead><tbody><tr><td>Strict EMI measurement accuracy is not required.<\/td><td>It is worth to try this method, if the main objective is to measure EMI frequencies, or relative EMI level among some types of EUT.<\/td><\/tr><tr><td>Enviromental noise in the laboratory is sufficiently smaller than EMI limit level.<\/td><td>The difference between the measured EMI and enviromental noise is equivalent to EMI from EUT.<\/td><\/tr><tr><td>Even if the enviromental noise at the specific frequency is relatively large, EMI from EUT at the same frequency is negligible.<\/td><td>Environmental noise that can be distinguished from the EMI may not be a big problem.<\/td><\/tr><\/tbody><\/table><\/figure><h3 class=\"vk_block-margin-md--margin-top wp-block-heading\" id=\"vk-htags-fc0fe98c-8759-477f-8fbb-83cd66720e70\">Calculation method to estimate EMI from EUT<\/h3><p>The EMI at every  frequency can be calculated by the fo llowing expression.<\/p><figure class=\"wp-block-image aligncenter\"><img decoding=\"async\" src=\"\/eng\/image\/application\/EMIkeisan_j-00.gif\" alt=\"Figure:\u8a08\u7b97\u5f0f\"\/><\/figure><p> The EMI can be measured by specctrum\/signal analyzer (338 E\/438E\/538E\/558E) with a function to calibrate properties of cable and antenna used. It is important t o subtract N from M  in linear [uV\/m], not in [dBuV\/m]. Measurement distance, and the height of EUT and the a ntenna should be the same to those of formal EMI test  site. If not taking into account the effect of the floor surfa ce reflection,  a certain configuration freedom may be provided. For example, in case of 2.5 m in measurement d istance, above estimated EMI can be corrected by adding a coefficient 20 log(2.5[m]\/3[m]) = -1.6[dB]. However, when  measurement distance is too short, there is a possibility that measurement error increases in the impact of near field of the antenna and EUT. <\/p><h3 class=\"vk_block-margin-md--margin-top wp-block-heading\" id=\"vk-htags-d6c8cc6a-b485-4f19-92a0-fb198f0edd12\">Discussion<\/h3><p>This EMI estimation approach is with an emphasis on co nvenience more than the measurement accuracy. The approach has been proposed as one of the solutions to  a very strong demand to need to understand EMI characteristics easily at low cost. If more accurate discussion is needed, issues to be co nsidered (ex. phase in subtraction operation, and influe nce of reflected wave from ceiling, wall, and floor) are not less.  But why don't you try to find a space in your laboratory suitable for simple EMI test with the handheld spectrum \/signal analyzer?  It is not necessarily exactly consist ent with the results at the regular test site, but you may f ind the place and the condition that it is operational as long as it is a relative evaluation in an acceptable error range.<\/p><h2 class=\"vk_block-margin-lg--margin-top wp-block-heading\" id=\"vk-htags-bfee73ad-7bfa-4cfa-939d-c69ffb2efa29\">System configuration<\/h2><figure class=\"wp-block-flexible-table-block-table\"><table class=\"\"><tbody><tr><td><a href=\"\/english\/products\/spectrum-analyzer\/msa500\/msa538e.html\">Signal analyzer [MSA538E]<\/a><\/td><\/tr><tr><td><a href=\"\/english\/products\/emc\/related-products\/map301.html\">Low noise amplifier MAP302<\/a><\/td><\/tr><tr><td>Jigs to mount antenna and EUT<\/td><\/tr><tr><td>Others(PC, I\/F modules, cables, etc)<\/td><\/tr><\/tbody><\/table><\/figure><p><\/p><p>*We will propose specifications that meet your needs.<\/p><h2 class=\"vk_block-margin-lg--margin-top wp-block-heading\" id=\"vk-htags-33bee439-d6ee-48ca-bd66-ea17d7acbc35\">Products introduction<\/h2><div class=\"wp-block-vk-blocks-select-post-list vk_posts vk_posts-postType-post vk_posts-layout-card-noborder vk_postList\"><div id=\"post-5785\" class=\"vk_post vk_post-postType-product card card-noborder vk_post-col-xs-12 vk_post-col-sm-6 vk_post-col-md-3 vk_post-col-lg-3 vk_post-col-xl-3 vk_post-col-xxl-3 post-2259 post type-post status-publish format-standard has-post-thumbnail hentry category-category-note tag-app-emc tag-app-knowledge tag-market-emc tag-application-emc tag-application-spectrum-analyzer\"><div class=\"vk_post_imgOuter\" style=\"background-image:url(https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620.png)\"><a href=\"https:\/\/micronix-jp.com\/english\/products\/spectrum-analyzer\/msa500\/msa538e.html\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"300\" src=\"https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620-300x300.png\" class=\"vk_post_imgOuter_img card-img-top wp-post-image\" alt=\"\" srcset=\"https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620-300x300.png 300w, https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620-150x150.png 150w, https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620-600x600.png 600w, https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620-100x100.png 100w, https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/msa538e_620x620.png 620w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/div><!-- [ \/.vk_post_imgOuter ] --><div class=\"vk_post_body card-body\"><h5 class=\"vk_post_title card-title\"><a href=\"https:\/\/micronix-jp.com\/english\/products\/spectrum-analyzer\/msa500\/msa538e.html\">Handheld Signal Analyzer MSA538E<\/a><\/h5><p class=\"vk_post_excerpt card-text\">This is a model in which EMI measurement function is added to MSA538.<br \/>\r\nMeasurement frequency : 20kHz to 3.3GHz <\/p><\/div><!-- [ \/.card-body ] --><\/div><!-- [ \/.card ] -->\n\n<div id=\"post-5802\" class=\"vk_post vk_post-postType-product card card-noborder vk_post-col-xs-12 vk_post-col-sm-6 vk_post-col-md-3 vk_post-col-lg-3 vk_post-col-xl-3 vk_post-col-xxl-3 post-2259 post type-post status-publish format-standard has-post-thumbnail hentry category-category-note tag-app-emc tag-app-knowledge tag-market-emc tag-application-emc tag-application-spectrum-analyzer\"><div class=\"vk_post_imgOuter\" style=\"background-image:url(https:\/\/micronix-jp.com\/english\/wp-content\/uploads\/sites\/2\/2023\/03\/map301_620x620.png)\"><a 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class=\"vk_post_body card-body\"><h5 class=\"vk_post_title card-title\"><a href=\"https:\/\/micronix-jp.com\/english\/products\/emc\/related-products\/map301.html\">Low Noise Amplifier MAP301\/302<\/a><\/h5><p class=\"vk_post_excerpt card-text\">Optimum for emission noise measurement.<\/p><\/div><!-- [ \/.card-body ] --><\/div><!-- [ \/.card ] --><\/div><p><\/p><div class=\"wp-block-vk-blocks-button vk_button vk_button-color-custom vk_button-366f95fc-5b71-4ff9-8a45-d2340dad3c00 vk_button-align-block\"><a href=\"\/eng\/file-download\/application\/pdf\/EMIkeisan_e.pdf\" class=\"vk_button_link btn has-background btn-lg btn-block\" role=\"button\" aria-pressed=\"true\" target=\"_blank\" rel=\"noopener\"><div class=\"vk_button_link_caption\"><i class=\"fas fa-file-pdf vk_button_link_before\" aria-hidden=\"true\"><\/i><span class=\"vk_button_link_txt\">Download This Application Note (PDF)<\/span><\/div><\/a><\/div><style type=\"text\/css\">.vk_button-366f95fc-5b71-4ff9-8a45-d2340dad3c00 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This paper [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":8201,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"vkexunit_cta_each_option":"","footnotes":""},"categories":[17],"tags":[44,47,66,71,75],"class_list":["post-2259","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-category-note","tag-app-emc","tag-app-knowledge","tag-market-emc","tag-application-emc","tag-application-spectrum-analyzer"],"_links":{"self":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/2259","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/comments?post=2259"}],"version-history":[{"count":3,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/2259\/revisions"}],"predecessor-version":[{"id":9559,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/2259\/revisions\/9559"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/media\/8201"}],"wp:attachment":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/media?parent=2259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/categories?post=2259"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/tags?post=2259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}