{"id":1797,"date":"2009-06-18T15:06:31","date_gmt":"2009-06-18T06:06:31","guid":{"rendered":"https:\/\/micronix-jp.com\/?p=1797"},"modified":"2023-03-20T17:11:53","modified_gmt":"2023-03-20T08:11:53","slug":"dtf_e_t1","status":"publish","type":"post","link":"https:\/\/micronix-jp.com\/english\/tech\/technology\/dtf_e_t1.html","title":{"rendered":"Principle and Procedures of DTF Measurement"},"content":{"rendered":"<section>\n<h2>Measurement Procedures<\/h2>\n\n<ol>\n  <li>\n  Read out the cable characteristics from USB memory<\/li>\n  <li>Set the rough value of distance to discontinuity point or cable length<\/li>\n  <li>Press the \u201cCF\/SPAN: Auto Set\u201d key<\/li>\n  <li>Select either\n    <ul>\n      <li>In case of 50\u03a9:Equip MA430 with 50\u03a9 terminator<\/li>\n      <li>In case of 75\u03a9:Equip with adapter cable MC313 and 50\u03a9\/75\u03a9 adapter MA310. Equip with MA310 75\u03a9 terminator.<\/li>\n  <\/ul>\n<\/li>\n<li>Execute the normalization<\/li>\n\n<li>Remove the terminator and connect the cable under test.<br>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"\/eng\/image\/technology\/dtf_e_t1-00.gif\" alt=\"Graph:A waveform of the cable in frequency\ndomain is observed\" width=\"521\" height=\"344\"><p>A waveform of the cable in frequency domain is observed<\/p><\/li>\n\n<li>Switch the mode to distance domain (Execute the Inverse Fourier Transform)\n\nThese processes are executed in MSA438TG automatically\n$$\n\\begin{cases}\n\n\u30fb\\text{IFT}:\n\\\\ \\quad\nf(t)=\\frac {1}{2\u03c0} \\int_{-\u221e}^\u221e F(j\u03c9) -exp[j\u03c9t]d\u03c9\n\\\\\n  \n\u30fb\\text{The time domain data is obtained}:\n\\\\\n\n\u30fb\\text{The time domain data is transformed into the distance domain}:\n\\\\ \\quad\n\\text{Distance\uff1dTime\u00d7(Propagation velocity)}\\\\\n\n\u30fb\\text{A waveform on distance domain is displayed}\n\\\\\n\n\n\n\\end{cases}\n$$\n\n<img loading=\"lazy\" decoding=\"async\" src=\"\/eng\/image\/technology\/dtf_e_t1-00.gif\" alt=\"Graph:A waveform on distance domain is displayed\" width=\"521\" height=\"344\">\n<p style=\"margin-top:0\">image:A waveform on distance domain is displayed<\/p>\n<\/li>\n\n<li>Measure the distance to the discontinuity point with a marker\n<\/li>\n\n<li>Save the measurement result in the USB memory<br>\n\n<div class=\"borderBoxAuto\">\n<i class=\"fas fa-square-full\" aria-hidden=\"true\"><\/i> Data saved in USB memory\n\n<ul class=\"flexBox flexBoxDivide\">\n  <li>\n<p style=\"margin-bottom:0\">Parameters related to measurement<\/p>\n\n  <table style=\"margin-bottom:2em;width:auto\">\n    <tbody><tr>\n      <th>DTF<\/th>\n      <th><\/th>\n    <\/tr>\n    <tr>\n      <td>Relative Propagation Velocity <\/td>\n      <td>0.659 <\/td>\n    <\/tr>\n    <tr>\n      <td>Nominal Attenuation (dB\/m) at 1GHz<\/td>\n      <td>0.787<\/td>\n    <\/tr>\n    <tr>\n      <td>Cable Attenuation(dB\/m)<\/td>\n      <td>0.00<\/td>\n    <\/tr>\n    <tr>\n      <td>Cable Length (m)<\/td>\n      <td>15<\/td>\n    <\/tr>\n    <tr>\n      <td>Length SPAN (m) <\/td>\n      <td>98.84<\/td>\n    <\/tr>\n    <tr>\n      <td>Factory Name <\/td>\n      <td>BLD<\/td>\n    <\/tr>\n    <tr>\n      <td>Cable Type<\/td>\n      <td>RG58A 58C<\/td>\n    <\/tr>\n    <tr>\n      <td>START f (MHz)<\/td>\n      <td>62.5<\/td>\n    <\/tr>\n    <tr>\n      <td>STOP f (MHz)<\/td>\n      <td>562.5<\/td>\n    <\/tr>\n  <\/tbody><\/table>\n<\/li>\n<li>  \n  <p style=\"margin-bottom:0\">1001 points waveform data on distance domain<\/p>\n  <table style=\"margin-bottom:2em;width:auto\">\n    <tbody><tr>\n      <th>spect_DTF<\/th>\n      <th><\/th>\n      <th><\/th>\n    <\/tr>\n    <tr>\n      <td class=\"price\">0<\/td>\n      <td class=\"price\">0<\/td>\n      <td class=\"price\">-47.84<\/td>\n    <\/tr>\n    <tr>\n      <td class=\"price\">\uff5e<\/td>\n      <td class=\"price\">\uff5e<\/td>\n      <td class=\"price\">\uff5e<\/td>\n    <\/tr>\n    <tr>\n      <td class=\"price\">1000<\/td>\n      <td class=\"price\">98.84<\/td>\n      <td class=\"price\">-56.13<\/td>\n    <\/tr>\n  <\/tbody><\/table>\n<\/li>\n<\/ul>\n<\/div>\n<\/li>\n<\/ol>\n<\/section>\n\n<section>\n<h2>Principle of DTF measurement<\/h2>\n\n<p>\n  <img loading=\"lazy\" decoding=\"async\" src=\"\/eng\/image\/technology\/dtf_e_t1-04.gif\" alt=\"image:Principle of DTF measurement\" width=\"730\" height=\"180\"><\/p>\n\n<p>\n  For this measurement, \u201cTG OUT\u201d of MSA438TG is divided into the cable under test and \u201cRF IN\u201d of MSA438TG by the DTF adapter. When a discontinuity point exists, the reflected signal returns to the DTF adapter. The half of reflected signal is input to the \u201cRF IN\u201d thorough the DTF adapter. The combined two signals of this reflected signal and \u201cTG OUT\u201d are input to \u201cRF IN\u201d. The mutual interference occurs corresponding to the frequency and the distance to discontinuity point of the cable. Therefore, peaks and bottoms are continuously generated on the frequency axis, and its frequency corresponds to the distance to discontinuity point. The reflection at the discontinuity point appears as a peak when this frequency domain data are converted into the time domain data by the inverse Fourier transform. And after then, the distance to discontinuity point is gotten by the multiplication of the appearance time of the peak and the propagation velocity. As the horizontal axis value of the marker measurement, the distance is displayed instead of the frequency in spectrum analyzer mode. Therefore, the distance can be directly read when the marker is moved to the peak. The processing mentioned above is done at each sweep.<\/p>\n\n<\/section><div class=\"wp-block-vk-blocks-button vk_button vk_button-color-custom vk_button-align-block\"><a href=\"\/eng\/file-download\/technical\/pdf\/dtf_e_t1.pdf\" style=\"background-color:#726756;border:1px solid #726756;color:#fff;\" class=\"vk_button_link btn btn-md btn-block white\" role=\"button\" aria-pressed=\"true\" target=\"_blank\"  rel=\"noopener\"><i class=\"fas vk_button_link_before fa-file-pdf\"><\/i><span class=\"vk_button_link_txt\">Download This Technical Report (PDF) <\/span><\/a><\/div><p><\/p><div class=\"wp-block-cover is-light vk_block-margin-xl--margin-top\"><span aria-hidden=\"true\" class=\"wp-block-cover__background has-white-background-color has-background-dim\"><\/span><img class=\"wp-block-cover__image-background wp-image-8105\" alt=\"\" src=\"https:\/\/micronix-jp.com\/wp-content\/uploads\/2022\/11\/contact_cta_cover.png\" data-object-fit=\"cover\"\/><div class=\"wp-block-cover__inner-container is-layout-flow wp-block-cover-is-layout-flow\"><p class=\"has-text-align-center has-huge-font-size\"><strong>Please feel free to contact us.<\/strong><\/p>\n\n<p>If you want to verify 5G, customize a radio wave shield box, or need product repair, please do not hesitate to contact us about any small matter.<\/p>\n\n<div class=\"wp-block-vk-blocks-grid-column vk_gridColumn\"><div class=\"row\"><div class=\"wp-block-vk-blocks-grid-column-item vk_gridColumn_item col-12 col-sm-12 col-md-12 col-lg-12 col-xl-12 col-xxl-12\"><div class=\"wp-block-vk-blocks-button vk_button vk_button-color-custom vk_button-align-block is-style-shine\"><a href=\"https:\/\/micronix-jp.com\/english\/contact\/\" class=\"vk_button_link btn has-background has-luminous-vivid-orange-background-color btn-lg btn-block\" role=\"button\" aria-pressed=\"true\" target=\"_blank\" rel=\"noopener\"><div class=\"vk_button_link_caption\"><i class=\"far fa-envelope vk_button_link_before\" aria-hidden=\"true\"><\/i><span class=\"vk_button_link_txt\"><strong>Contact Form<\/strong><\/span><\/div><\/a><\/div><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Measurement Procedures Read out the cable characteristics from USB memory Set the rough value of distance to discontinuity point or cable length Press the \u201cCF\/SPAN: Auto Set\u201d key Select either [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":8261,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"vkexunit_cta_each_option":"","footnotes":""},"categories":[32],"tags":[86],"class_list":["post-1797","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-category-technology","tag-technology-spectrum-analyzer"],"_links":{"self":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/1797","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=1797"}],"version-history":[{"count":1,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/1797\/revisions"}],"predecessor-version":[{"id":6990,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/posts\/1797\/revisions\/6990"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/media\/8261"}],"wp:attachment":[{"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/media?parent=1797"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/categories?post=1797"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/micronix-jp.com\/english\/wp-json\/wp\/v2\/tags?post=1797"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}